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Compensatory growth is a feeding management strategy well documented in the literature. However, the molecular and histological effects on fish still require further knowledge. This study determined the biometric, morphological, and histometric changes in adults of catfish (Lophiosilurus alexandri) after chronic fasting. Sixty adults (396.6 ± 77.5 g) were tagged with microchips and distributed in two tanks (n = 30/tank), one with normal feed and the other with total food restriction for 60 d and then refed for another 15 d. Tissue and biometric samples were taken on days 20, 40, 60 and 75. Fish reared under chronic fasting presented weight loss and had significantly lower intestinal villi height, goblet cells and muscularis thickness than those fed on a control diet. In summary, a chronic food restriction protocol can change morphology and the 15-d refeeding period was not enough to reestablish the morphological parameters and weight of L. alexandri. [ABSTRACT FROM AUTHOR]

Schizothorax lissolabiatus and Schizothorax griseus are native Chinese fish species with significant ecological and economic importance. We wanted to support sustainable aquaculture practices by exploring the differences in metabolic, histological, and microbiota between the two Schizothorax species. This study analyzed and compared the digestive enzyme activities, metabolic indicators, gut histology, and microbiota composition of S. lissolabiatus and S. griseus under identical farming conditions. Our comparative analysis reveals both shared characteristics and species-specific differences. While a-amylase and trypsin activities showed no significant differences between species, a consistent trend was observed, with enzyme activity highest in the hindgut, followed by the midgut, foregut, esophagus, and liver. In terms of specific metabolic markers, S. griseus shows higher lipase activity in the liver and foregut, as well as higher aspartate aminotransferase and catalase levels in the liver, along with an increased serum glucose content compared to S. lissolabiatus. Serum metabolomics analysis revealed 21 differentially abundant metabolites linked to glycerophospholipid metabolism, autophagy, purine metabolism, and necroptosis, reflecting distinct metabolic adaptations and nutritional needs for each species. These metabolic differences provide a basis for optimizing feed composition and aquaculture practices tailored to each species. Notably, S. lissolabiatus displays a significantly higher goblet cell count in the hindgut compared to S. griseus. Additionally, both species exhibit greater villi number, length, width, crypt depth, and muscle thickness in the esophagus than in the foregut, midgut, and hindgut. S. griseus also has a higher number of operational taxonomic units (OTUs) and greater microbial diversity in its intestinal microbiota, which may enhance its nutrient utilization capabilities. While both species’ dominant microbial phyla include Fusobacteria, Firmicutes, Proteobacteria, and Bacteroidetes, S. griseus demonstrated superior lipid digestion capabilities. Furthermore, the midgut and hindgut in both species display higher starch and protein digestive enzyme activities than other digestive tissues. These findings highlight the physiological differences between the two Schizothorax species, suggesting targeted strategies to improve health, growth, and sustainability in aquaculture.

Mandarin fish (Siniperca chuatsi) fed with an artificial diet is progressively gaining popularity, which is important for reducing product prices and resource consumption. However, food is the decisive factor of intestinal microbes, and the profound effects of change in their feeding habit on intestinal microbes of mandarin fish have not been revealed. In the present study, live bait fish and artificial diet were used to feed mandarin fish for 8 weeks to study the effect of different feeding habits on the histology, microbiota structure and dominant bacteria of gut in mandarin fish. The results indicated that feeding with the artificial diet significantly increased the intestinal villi height and muscular thickness in the hindgut of mandarin fish. In addition, the microbiota results showed that there were significant differences of beta diversity of gut microbiota in mandarin fish fed with different diets. At the genus level, feeding artificial diets significantly increased the abundance of Weissella in the mandarin fish gut. Furthermore, two Weissella bacteria were identified and characterized from the midgut contents of mandarin fish fed with artificial diet. Based on 16S rRNA gene sequencing, nine strains were assigned as Weissella confusa (RM125), and one as Weissella cibaria (SJ548). Biochemical analyses based on the VITEK2 method revealed a pattern of metabolic activities against W. confusa RM125 and W. cibaria SJ548, with 13 positive and 29 negative results, respectively. W. confusa RM125 and W. cibaria SJ548 exhibited sensitivities toward a variety of pathogens, including V. harveyi, S. aureus and V. parahaemolyticus, E. coli, A. hydrophila, S. enterica, V. anguillarum, and V. alginolyticus, indicating potential probiotics. Therefore, our results confirmed that the transformation of feeding habit altered the structure, microbial composition and dominant bacteria in gut of mandarin fish, and provided evidence that Weissella might play a crucial role in the digestion and absorption of artificial diet in mandarin fish.

This study was conducted to ascertain the negative effects of dietary low-density polyethylene microplastics (LDPE-MPs) exposure on growth, nutrient digestibility, body composition and gut histology of Nile tilapia (Oreochromis niloticus). Six sunflower meal-based diets (protein 30.95%; fat 8.04%) were prepared; one was the control (0%) and five were incorporated with LDPE-MPs at levels of 2, 4, 6, 8 and 10% in sunflower meal-based diets. A total of eighteen experimental tanks, each with 15 fingerlings, were used in triplicates. Fish were fed at the rate of 5% biomass twice a day for 60 days. Results revealed that best values of growth, nutrient digestibility, body composition and gut histology were observed by control diet, while 10% exposure to LDPE-MPs significantly (P < 0.05) reduced weight gain (WG%, 85.04%), specific growth rate (SGR%, 0.68%), and increased FCR (3.92%). The findings showed that higher level of LDPE-MPs (10%) exposure in the diet of O. niloticus negatively affects nutrient digestibility. Furthermore, the results revealed that the higher concentration of LDPE-MPs (10%) had a detrimental impact on crude protein (11.92%) and crude fat (8.04%). A high number of histological lesions were seen in gut of fingerlings exposed to LDPE-MPs. Hence, LDPE-MPs potentially harm the aquatic health. [ABSTRACT FROM AUTHOR]

Fishmeal and fish oil substitution in aquafeeds might have adverse effects on fish growth and health, mainly in carnivorous species, such as Mediterranean yellowtail (Seriola dumerili). Mediterranean yellowtail shows great potential as an alternative aquaculture species due to its fast growth and high price on the market, but the need for high-quality protein and fatty acid content in its diets is limiting its production. In order to improve the sustainability of its production, this study was conducted with 360 fish of 35 g to evaluate the effects on fish growth and health. Six diets were used: one control diet without replacement, three with FM replacement (FM66, FM33, and FM0) (33%, 66%, and 100% FM replacement), and two with FO replacement (FO50 and FO0) (50% and 100% FO replacement). The substitution of FM was with vegetable (VM) (corn gluten) and animal (AM) (krill and meat meal) meals. The reductions in FM and FO of up to 33 and 0%, respectively, did not affect the growth and survival of S. dumerili at the intestinal morphology level, except for the anterior intestine regarding the lower villi length and width and the posterior intestine regarding the lower width of the lamina propria. On the other hand, the substitution of fish ingredients in the diet affects liver morphology, indicating alterations in the major diameter of hepatocytes or their nuclei. Finally, diet did not affect the gut microbiota with respect to the control, but significant differences were found in alpha and beta diversity when FO and FM microbiota were compared. A 66% FM replacement and total FO replacement would be possible without causing major alterations in the fish.

The replacement of fishmeal (FM) with economical and nutritious FM alternatives including plant- and animal-based protein ingredients has become a global research priority. However, the presence of several anti-nutritional factors (ANFs) in these alternatives may impair nutrient utilization in fish. The supplementation of exogenous protease as feed additives could be an effective approach to improve the nutrient digestibility of these alternative proteins. Proteases are protein-digesting enzymes that catalyze the hydrolysis of complex protein macromolecules into simpler amino acids. Exogenous protease supplementation stimulates the activities of endogenous proteolytic enzymes for better nutrient digestion and absorption in fish. This review article summarizes the optimum protease supplementation levels in various fish species and its beneficial effects on growth performance, nutrient digestibility, intestinal morphology, digestive enzyme activities, whole-body composition, physiochemical parameters, immunity, and gene expression of fish. Moreover, the interactive effects of exogenous protease with organic acids and probiotics are also discussed. Overall, the supplementation of exogenous protease in fish feed is a viable solution for poor nutrient utilization of FM alternatives. Important gaps, however, exist in the current knowledge, particularly with regard to the effect of protease supplementation in animal-based proteins as most of the studies have focused on the effect of protease supplementation on plant-based proteins as FM alternatives. Moreover, additional studies focused on the effect of protease supplementation on the digestive enzyme activities, immunity, gut microbes and antioxidant parameters of fish will provide the basis for a better understanding of the mode of action of protease. The scarce knowledge in these areas limits the scope of protease supplementation as a feed additive in the aquaculture sector. [ABSTRACT FROM AUTHOR]

Abstract Microplastics (MPs) are emerging pollutants that may affect the aquatic life, including fish, raised in aquaculture. The purpose of this study was to determine the effects of biodegradable-MPs mixed in canola meal based diet on the growth performance, body composition, nutrient digestibility and gut content of grass carp fingerlings. For this purpose, six canola meal based diets were prepared including one control diet (without addition of MPs) and five other diets containing 1%, 3%, 5%, 7% and 9% MPs. 270 fingerlings were fed twice for 60 days at a rate of 5% of their wet weight. Effect of each treatment on the weight gain, feed conversion ratio (FCR), nutrient digestibility, gut performance and body composition was calculated by standard procedures. Highest value for growth, nutrient digestibility and no damage to gut was observed in fish fed control diet. Results showed that there was significant decrease (P

This study evaluated the status of the well-being of wild Nandus nandus in the Kawadighi Haor through morphometric and gastrointestinal indices and local people’s perceptions. Basic macroscopic morphology of the gastrointestinal tract (GIT), the viscera somatic index (VSI), the hepatosomatic index (HSI), the condition factor (K), length–weight relationships, and gut histology were analyzed from the regular commercial catch. The GIT morphology includes a tube-like esophagus, a tapering stomach, a tubular intestinal region, and a rectum, all of which have clinically normal shapes and conditions. VSI and HSI values fluctuate throughout the year, indicating the periodic variation of food content and availability in the ecosystem. The condition factor (K) was generally stable, with minor deviations in December. The mucosa, submucosa, muscularis, and serosa were identified from the stomach of N. nandus and showed normal histological characteristics. There were numerous proliferated villi in the tunica mucosa, but no histopathological abnormalities were found in the gut. These findings suggest that the current population of N. nandus in the Haor is in a favorable condition. However, local people reported some potential threats that might be a concern for the long-term survival of this species. The results of the present study will be useful for effective and sustainable stock management of the N. nandus fishery in the Kawadighi Haor and other floodplain ecosystems.

We investigated the beneficial dietary effects of mannan oligosaccharide (MOS) on sea cucumber (Apostichopus japonicus) and the optimum dietary level of MOS. Juvenile sea cucumbers (initial mean weight of 1.50 ± 0.00 g, N = 225) were fed once daily for 60 days in tanks with aerated seawater (3 tanks/diet; 15 inds/tank) on feeds supplemented with 0 g/kg (M0), 4 g/kg (M1), 8 g/kg (M2), 12 g/kg (M3), and 16 g/kg (M4) MOS. The results showed that 4 g/kg of MOS in feeds significantly improved the growth performance of sea cucumber. There was a positive linear and quadratic correlation between the total superoxide dismutase (T-SOD) activity and dietary MOS level (linear, P = 0.043, R2 = 0.279; quadratic, P = 0.009, R2 = 0.545). Compared with the control group, 8 g/kg MOS significantly increased the protease (PRO) and amylase (AMS) activities (P < 0.05). Quadratic regression was observed between PRO and dietary MOS level (P = 0.022, R2 = 0.470). Moreover, M2 diets significantly increased the muscular thickness and width of mucosal folds of sea cucumber than in the M0 group (P < 0.05). Base on the quadratic regression between muscular thickness and dietary MOS level was also observed , the optimal level of MOS for intestinal muscular thickness 8 g/kg. High-throughput sequencing was used to analyze the diversity and relative abundance of microorganisms. Proteobacteria, Firmicutes, and Bacteroidetes represented the most abundant phyla in each sample. There was a positive correlation between the expression of heat shock protein 70 (HSP70) (P = 0.015, R2 = 0.503) and heat shock protein 90 (Hsp90) (HSP90a: P = 0.016, R2 = 0.496; HSP90b (linear, P = 0.049, R2 = 0.266; quadratic, P = 0.015, R2 = 0.505)) with dietary MOS levels. However, a negative correlation was observed for the expression of major yolk protein (MYP) and proprotein convertase subtilisin kexin 9 (PCSK9) and dietary MOS levels. The present results showed that dietary MOS supplementation enhanced the antioxidant capacity and immunity, increased the abundance and diversity of intestinal microbiota, improved intestinal morphology, and enhanced thermal stress tolerance of sea cucumber. The optimal dietary MOS concentration was 4−8 g/kg. [ABSTRACT FROM AUTHOR]

This study evaluated the status of the well-being of wild Nandus nandus in the Kawadighi Haor through morphometric and gastrointestinal indices and local people's perceptions. Basic macroscopic morphology of the gastrointestinal tract (GIT), the viscera somatic index (VSI), the hepatosomatic index (HSI), the condition factor (K), length–weight relationships, and gut histology were analyzed from the regular commercial catch. The GIT morphology includes a tube-like esophagus, a tapering stomach, a tubular intestinal region, and a rectum, all of which have clinically normal shapes and conditions. VSI and HSI values fluctuate throughout the year, indicating the periodic variation of food content and availability in the ecosystem. The condition factor (K) was generally stable, with minor deviations in December. The mucosa, submucosa, muscularis, and serosa were identified from the stomach of N. nandus and showed normal histological characteristics. There were numerous proliferated villi in the tunica mucosa, but no histopathological abnormalities were found in the gut. These findings suggest that the current population of N. nandus in the Haor is in a favorable condition. However, local people reported some potential threats that might be a concern for the long-term survival of this species. The results of the present study will be useful for effective and sustainable stock management of the N. nandus fishery in the Kawadighi Haor and other floodplain ecosystems. [ABSTRACT FROM AUTHOR]

Simple Summary: The sustainability and further development of an intensive aquaculture of carnivores have been threatened in recent years by their dependence on fishmeal and fish oil. Alternative ingredients are therefore necessary to promote sustainable aquaculture production without compromising fish growth and health. Use of insects as an alternative protein source for aquaculture feed production is an excellent example of circular economy. Among insects, Hermetia illucens is one of the most promising sustainable protein and lipid sources. This study aimed to evaluate the effects of partially defatted HIM dietary inclusion on growth performance, stress indicators and gut histological traits of Sparus aurata. The feeding trial was carried out on 312 fish fed with a basal diet containing only fish meal as a protein source of animal origin, and three diets (HIM25, HIM35 and HIM50) containing 25%, 35% and 50% defatted Hermetia illucens meal as a partial replacement for fishmeal. The trial lasted 131 days. The results show that the insect meal inclusion did not affect growth performance and blood parameters and the health of the posterior gut tract, while the inclusion level at the 50% caused morphometric and histopathological changes in the anterior gut tract. Among the diets, the HIM35 was the most tolerated formulation by fish. This study provided new data and knowledge on the potential use of Hermetia illucens meal (HIM) as a new sustainable ingredient for Sparus aurata diet. The effect of HIM dietary inclusion on fish growth performance, stress indicators and gut histology was studied. For 131 days, 312 fish were fed a basal diet containing fishmeal as animal protein source, and three diets containing 25%, 35% and 50% HIM as a partial replacement for fishmeal. The main findings indicated that fishmeal can be replaced by HIM up to 110 g/kg of substitution (35% of inclusion in diet) without negative effects on growth performance, stress parameters or histological traits of the posterior gut tract, and with positive effects (p < 0.05) on the histological and morphometric characteristics of the anterior gut tract. At the same time, the results showed that the effect of Hermetia illucens meal at 50% inclusion level caused morphometric and histopathological alterations in the anterior gut tract of seabream. In conclusion, this preliminary study suggested that the dietary inclusion level of HIM35 was the most tolerated by fish showing the best gut morphometric parameters and histological conditions, with fewer signs of inflammation, as well as good nutritional and health status. [ABSTRACT FROM AUTHOR]

The study evaluated the effects of dietary phosphorus supplementation on the fishmeal replacement with Clostridium autoethanogenum protein (CAP) in the diet of L. vannamei. Four isonitrogenous and isolipid diets were formulated: the PC diet contains 25% fishmeal, the NC, P1 and P2 diets were replaced 40% fishmeal with CAP and supplemented with 0, 0.8 and 1.6% NaH 2 PO 4 respectively (equivalent to dietary phosphorus level of 0.96%, 1.12% and 1.27%). Sampling and V. parahaemolyticus challenge test were conducted after 50-day-feeding (initial shrimp weight 1.79 ± 0.02 g). The results showed that there were no significant differences in the growth performance of shrimp among the 4 groups. The expressions of dorsal in the gut were significantly lower in shrimp fed the P1 and P2 diets than shrimp fed the NC diet and the expression of peroxinectin in the gut was lower in shrimp fed the NC diet than others. The cumulative mortality of shrimp after V. parahaemolyticus challenge was significantly lower in shrimp fed the P2 diet than those fed the NC diet. After the challenge, genes expressions related to the prophenoloxidase activating system (proPO , lgbp , ppaf) were inhibited in the hepatopancreas of shrimp fed NC diet but activated in shrimp fed the P1 diet compared to those fed the PC diet. The AKP and T-AOC activities were higher in shrimp fed the P2 diet than those fed the other diets. The thickness of muscle layer of shrimp fed the P1 diet was thicker than that in the other groups, and significant stress damage happened in the midgut of the shrimp fed the NC diet. The abundance of Pseudoalteromonas , Haloferula and Ruegeria in shrimp fed the P1 diet was higher than those fed the other diets, while Vibrio in shrimp fed the P2 diet was higher than those fed the other diets. This indicated that a low fishmeal diet with dietary phosphorus level of 1.12% could improve the histology, enhance immune response, and increase the abundance of beneficial bacteria in the gut of shrimp. The low fishmeal diet with dietary phosphorus level of 1.27% could improve disease resistance and antioxidant capacity, but there was a possibility of damage to the gut histology as well as increasing abundance of Vibrio in the gut microbiota of shrimp. • The feasibility of supplementing Dietary phosphorus based on the 40% fishmeal replacement with C. autoethanogenum protein in the diet of Pacific white shrimp. • Dietary phosphorus level of 1.12% could improve the health of the gut of shrimp, while the level of 1.27% could enhance the disease resistance. [ABSTRACT FROM AUTHOR]

Simple Summary: Obtaining superior eggs and larvae is the first stage toward sustainable aquaculture. The production of aquatic animal larvae is frequently obstructed by high death rates, and water-soluble stimulants are suggested to be more effective in the early stages, e.g., eggs and yolk larvae stage. A limited number of studies exist on the use of coenzyme Q10 (CoQ10) in aquaculture, particularly as a dietary supplement, and to the authors' knowledge, there are insufficient studies on the application of CoQ10 as a water treatment. Therefore, this study attempted to evaluate the possible impacts of the exposure of red tilapia eggs to CoQ10 in hatching water. Red tilapia eggs one day post fertilization (dpf) were exposed to coenzyme Q10 (CoQ10) at rates of 0, 5, and 10 mg/L for control, treatment 2 (C5), and treatment 3 (C10), respectively, without exchanging water and until the larval mouth-opening stage. Fertilized eggs of red tilapia exposed to different concentrations of CoQ10 were hatched at rates (p > 0.05) between 38 to 54.67%. The yolk-sac diameter at the 2nd day post hatching (dph), ranged from 1.85 to 1.87 mm in depth and 1.63 to 1.88 mm in width and was not altered by the CoQ10 treatments. Similarly, red tilapia survival (p > 0.05) ranged from 22.67 to 32%. On 6 dph, a slight percentage (2.08%) of survived fishes exposed to high CoQ10 dose (C10) exhibited larval deformation in the form of an axial curvature of the spine in the abdominal and caudal region. Larvae displayed a normal structure of the esophagus folds in all fish groups, and larvae in the C5 group displayed the longest folds and widest muscularis layer, followed by fishes in the C10 group and the control. Red tilapia fry on 30 dph treated with CoQ10 possessed higher antioxidant potentials in terms of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) compared to the control. In conclusion, treating Red tilapia fertile eggs with 5 mg/L CoQ10 improves the growth, gut structure, and antioxidant efficiency of the produced larvae. [ABSTRACT FROM AUTHOR]

Abstract Background The use of plant-based formulations is an easy and economical method to control insect pests. The objectives of the present study were to evaluate ovicidal and larvicidal potential of ethanolic leaf extracts of four plants, Cyathocline purpurea, Blumea lacera, Neanotis lancifolia, and Neanotis montholonii, and their effects on gut histology of Aedes aegypti (Diptera: Culicidae) larvae. We identified the phytochemicals present in the ethanolic extracts of these plants by LC-MS analysis. The eggs and larvae of A. aegypti were exposed to four concentrations (0.05, 0.1, 0.2, and 0.3 mg/mL) of crude ethanol extracts for different time durations. We observed egg hatching for 48 h, mortality, and gut histology of the 3rd instar larvae after 24, 48, and 72 h of treatments. Results LC-MS analysis revealed the presence of various active compounds such as alkaloids, tannins, saponins, and flavonoids in the ethanol extracts of all these plants. The extracts of all plants showed ovicidal activity. The extracts of C. purpurea showed the highest larvicidal activity (LC50 at 72 h = 0.088 mg/mL) followed by B. lacera (LC50 at 72 h = 0.758 mg/mL) while N. lancifolia and N. montholonii extracts did not show significant larvicidal activity. All plant extracts affected gut morphology in concentration and treatment duration-dependent manner. The plant extracts used in the present study have ovicidal properties and affected the gut histology of A. aegypti larvae. Conclusion These results suggest that C. purpurea has the highest larvicidal activity against A. aegypti larvae and can be further evaluated for application purposes.

This study investigated the dietary effect of Spirulina platensis phycocyanin (SPC) on growth performance (body weight (BW), body weight gain (BWG), feed intake (FI), feed conversion ratio (FCR)) at starter, grower, and finisher stages, intestinal histomorphology, serum biochemical parameters, inflammatory and antioxidant indices, and proinflammatory cytokines (tumor necrosis factor-α and caspase-3) immune expression in broiler chickens. In total, 250 one-day-old chicks (Ross 308 broiler) were randomly allotted to five experimental groups (5 replicates/group, 10 chicks/replicate) and fed basal diets supplemented with five levels of SPC (0, 0.25, 0.5, 0.75, and 1 g kg–1 diet) for 35 days. Compared with SPC0 treatment, different SPC levels increased the overall BW and BWG without affecting the total feed consumption. However, the FCR decreased linearly with an increase in supplementation level. The serum levels of total proteins, albumin, globulins, and growth hormone increased linearly by increasing levels of SPC supplementation. Further, SPC supplementation increased the thyroxin hormones without affecting serum glucose and leptin levels. Serum total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) values decreased in broilers fed SPC0.250 and SPC1 diets. Triglycerides (TG) decreased in SPC0.25-, SPC0.75-, and SPC1-treated groups. Though antioxidant enzyme activities (total antioxidant capacity, catalase, and superoxide dismutase) increased linearly and quadratically, malondialdehyde (MDA) decreased linearly by increasing the SPC level. There was no effect on serum proinflammatory cytokines IL1β levels. Immunolabelling index of caspase-3 and tumor necrosis factor-α (TNF-α) were downregulated by SPC supplementation. The intestinal histomorphology is represented by increased villus height, the villus height to crypt depth ratio, and numbers of goblet cells in different sections of the small intestine. In conclusion, SPC supplementation is beneficial in broiler chicken diets due to its growth-promoting, antioxidant, and anti-inflammatory properties. [ABSTRACT FROM AUTHOR]

This study provided new data and knowledge on the potential use of Hermetia illucens meal (HIM) as a new sustainable ingredient for Sparus aurata diet. The effect of HIM dietary inclusion on fish growth performance, stress indicators and gut histology was studied. For 131 days, 312 fish were fed a basal diet containing fishmeal as animal protein source, and three diets containing 25%, 35% and 50% HIM as a partial replacement for fishmeal. The main findings indicated that fishmeal can be replaced by HIM up to 110 g/kg of substitution (35% of inclusion in diet) without negative effects on growth performance, stress parameters or histological traits of the posterior gut tract, and with positive effects (p < 0.05) on the histological and morphometric characteristics of the anterior gut tract. At the same time, the results showed that the effect of Hermetia illucens meal at 50% inclusion level caused morphometric and histopathological alterations in the anterior gut tract of seabream. In conclusion, this preliminary study suggested that the dietary inclusion level of HIM35 was the most tolerated by fish showing the best gut morphometric parameters and histological conditions, with fewer signs of inflammation, as well as good nutritional and health status.

This study aimed to evaluate the effects of a mixture of olive, laurel, and rosemary leaf powders, on the oxidative state, biochemical, immune, intestinal morphophysiological parameters, and egg quality of laying hens. One hundred Lohmann Brown hens (28 weeks old) were equally assigned to two groups (n. 50) corresponding to a basal control diet (CON) or the diet supplemented with 6 g/kg feed of leaf powder mixture (LPM) containing olive, laurel, and rosemary leaves (1:1:1), for 60 days. Oxidative status, biochemical indices, immune response, cecal short chain fatty acids (SCFAs), intestinal morphological characteristics, and some egg traits were evaluated at the end of the experiment. The results indicated that LPM improved (P < 0.05) the oxidative status (TOS, ROMs), the immune system (IL-6, IL-1β, and TNF-α), the total protein and HDL cholesterol content, whereas it decreased (P < 0.05) total cholesterol and LDL cholesterol. Aspartate aminotransferase (AST), alkaline phosphatase (ALP), and alanine aminotransferase were significantly (P < 0.05) lower in the LPM than in the CON group. A significant increase (P < 0.05) in SCFA content in the caecum, as well as in villi height and crypt depth in both duodenum and ileum of LPM-treated hens, was observed. Egg quality parameters were not influenced (P > 0.05) by LPM. These findings indicate that LPM can be considered a candidate as an antioxidant ingredient for functional food in laying hens., Competing Interests: Declaration of competing interest The authors of this manuscript have no financial or personal relationships that could potentially influence the content and findings presented in the manuscript., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

We evaluated the growth, gut histomorphometry, selected immune responses and resistance of Nile tilapia (Oreochromis niloticus) against Streptococcus agalactiae infection when fed VILIGEN™, an additive blend containing sodium butyrate, dehydrated hydrolysed yeast and zinc proteinate. Increasing doses (0.00, 0.60, 1.20, 2.40 and 4.80 g kg−1) were added to a basal diet and randomly assigned to six groups, each with 28 fish. The fish were fed to satiation twice daily for 60 days, infected via gavage with S. agalactiae at 1.0 × 109 CFU ml−1, and mortality was recorded for 14 days. Dietary inclusion of VILIGEN™ promoted higher weight gain, gut‐fold perimeter and the number of goblet cells. Through polynomial regression, the optimal inclusion level for these variables was estimated at 2.80, 3.30 and 3.50 g kg−1, respectively. However, there was no clear effect of the additive on the immune responses tested before bacterial infection or in the survival after challenge. This is the first study on VILIGEN™ supplementation in fish diets. Higher growth and altered gut morphology were seen with the inclusion of VILIGEN™ in the range of 2.80 to 3.50 g kg−1 but the response to the bacterial challenge was not clearly affected. [ABSTRACT FROM AUTHOR]

Agrochemicals including cypermethrin (cyp) and thiourea are increasingly being applied in modern agriculture, for pest control and to improve crop yield. However, their usage often results in serious environmental concerns. In this study, juvenile African catfish Clarias gariepinus (Burchell 1822) were exposed to 50 µg/L cyp, 100 µg/L cyp, 0.05% thiourea, 50 µg/L cyp + 0.05% thiourea or 100 µg/L cyp + 0.05% thiourea, in a static renewal for 3 weeks, after which the fish were sacrificed, and the level of reduced glutathione and activities of acid phosphatase, alkaline phosphatase, amylase, protease and lipase were determined in the liver or intestinal homogenates. Also, the histopathology of some sections of the intestine was performed. The control fish were maintained in uncontaminated water (i.e. not exposed to cypermethrin or thiourea). The individual exposure of fish to cypermethrin and thiourea resulted in a significant decrease in the levels of GSH and the activities of most of the enzymes. These effects were more pronounced in fish that were exposed to cypermethrin and thiourea under a co-exposure scenario. The histological analyses of some sections of the intestine also revealed the toxicological effect of these agrochemicals, and their use led to visible intestinal pathologies such as severe erosion of the mucosa layer, faded lamina propria and disintegration of the muscle layer. The results of this study demonstrate that both cypermethrin and thiourea can alter the redox status and nutritional physiology of fish. The greater toxic effects of cypermethrin and thiourea under the co-exposure condition reiterated the potential for interactions and synergistic relationship among toxicants. [ABSTRACT FROM AUTHOR]

Red tilapia eggs one day post fertilization (dpf) were exposed to coenzyme Q10 (CoQ10) at rates of 0, 5, and 10 mg/L for control, treatment 2 (C5), and treatment 3 (C10), respectively, without exchanging water and until the larval mouth-opening stage. Fertilized eggs of red tilapia exposed to different concentrations of CoQ10 were hatched at rates (p > 0.05) between 38 to 54.67%. The yolk-sac diameter at the 2nd day post hatching (dph), ranged from 1.85 to 1.87 mm in depth and 1.63 to 1.88 mm in width and was not altered by the CoQ10 treatments. Similarly, red tilapia survival (p > 0.05) ranged from 22.67 to 32%. On 6 dph, a slight percentage (2.08%) of survived fishes exposed to high CoQ10 dose (C10) exhibited larval deformation in the form of an axial curvature of the spine in the abdominal and caudal region. Larvae displayed a normal structure of the esophagus folds in all fish groups, and larvae in the C5 group displayed the longest folds and widest muscularis layer, followed by fishes in the C10 group and the control. Red tilapia fry on 30 dph treated with CoQ10 possessed higher antioxidant potentials in terms of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) compared to the control. In conclusion, treating Red tilapia fertile eggs with 5 mg/L CoQ10 improves the growth, gut structure, and antioxidant efficiency of the produced larvae.

Background: The use of plant-based formulations is an easy and economical method to control insect pests. The objectives of the present study were to evaluate ovicidal and larvicidal potential of ethanolic leaf extracts of four plants, Cyathocline purpurea, Blumea lacera, Neanotis lancifolia, and Neanotis montholonii, and their effects on gut histology of Aedes aegypti (Diptera: Culicidae) larvae. We identified the phytochemicals present in the ethanolic extracts of these plants by LC-MS analysis. The eggs and larvae of A. aegypti were exposed to four concentrations (0.05, 0.1, 0.2, and 0.3 mg/mL) of crude ethanol extracts for different time durations. We observed egg hatching for 48 h, mortality, and gut histology of the 3rd instar larvae after 24, 48, and 72 h of treatments. Results: LC-MS analysis revealed the presence of various active compounds such as alkaloids, tannins, saponins, and flavonoids in the ethanol extracts of all these plants. The extracts of all plants showed ovicidal activity. The extracts of C. purpurea showed the highest larvicidal activity (LC50 at 72 h = 0.088 mg/mL) followed by B. lacera (LC50 at 72 h = 0.758 mg/mL) while N. lancifolia and N. montholonii extracts did not show significant larvicidal activity. All plant extracts affected gut morphology in concentration and treatment duration-dependent manner. The plant extracts used in the present study have ovicidal properties and affected the gut histology of A. aegypti larvae. Conclusion: These results suggest that C. purpurea has the highest larvicidal activity against A. aegypti larvae and can be further evaluated for application purposes. [ABSTRACT FROM AUTHOR]

This study investigated the dietary effect of Spirulina platensis phycocyanin (SPC) on growth performance (body weight (BW), body weight gain (BWG), feed intake (FI), feed conversion ratio (FCR)) at starter, grower, and finisher stages, intestinal histomorphology, serum biochemical parameters, inflammatory and antioxidant indices, and proinflammatory cytokines (tumor necrosis factor-α and caspase-3) immune expression in broiler chickens. In total, 250 one-day-old chicks (Ross 308 broiler) were randomly allotted to five experimental groups (5 replicates/group, 10 chicks/replicate) and fed basal diets supplemented with five levels of SPC (0, 0.25, 0.5, 0.75, and 1 g kg–1 diet) for 35 days. Compared with SPC0 treatment, different SPC levels increased the overall BW and BWG without affecting the total feed consumption. However, the FCR decreased linearly with an increase in supplementation level. The serum levels of total proteins, albumin, globulins, and growth hormone increased linearly by increasing levels of SPC supplementation. Further, SPC supplementation increased the thyroxin hormones without affecting serum glucose and leptin levels. Serum total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) values decreased in broilers fed SPC0.250 and SPC1 diets. Triglycerides (TG) decreased in SPC0.25-, SPC0.75-, and SPC1-treated groups. Though antioxidant enzyme activities (total antioxidant capacity, catalase, and superoxide dismutase) increased linearly and quadratically, malondialdehyde (MDA) decreased linearly by increasing the SPC level. There was no effect on serum proinflammatory cytokines IL1β levels. Immunolabelling index of caspase-3 and tumor necrosis factor-α (TNF-α) were downregulated by SPC supplementation. The intestinal histomorphology is represented by increased villus height, the villus height to crypt depth ratio, and numbers of goblet cells in different sections of the small intestine. In conclusion, SPC supplementation is beneficial in broiler chicken diets due to its growth-promoting, antioxidant, and anti-inflammatory properties.

The present study aims to isolate, identify, and evaluate potential probiotic, Lactic Acid Bacteria (LAB) from the gut and hepatopancreas of 10 healthy wild giant freshwater prawn, Macrobrachium rosenbergii. The samples were cultivated using a modified De Man, Rogosa and Sharpe (MRS) agar supplemented with 2% of CaCO3 (w/v). Bacterial colonies with strong clear zone were selected for further tests. From these, 17 isolates of LAB showed non-spore forming, homofermentative characteristics, Gram-positive, rod-shaped, non-motile bacteria and absences of catalase enzymes. The LAB was further identified using API 50 CH kit and 16S rRNA. The isolates LAB also showed tolerance to a variety of environmental conditions like pH, temperature, salt, bile and hemolysis activity in in vitro condition. Based on the results, two isolates LAB were identified as Lactobacillus plantarum and Entercoccus faecalis were suggested as potential probiotic candidates from giant freshwater prawn for Aquaculture industries.

Abstract Background Campylobacters are an unwelcome member of the poultry gut microbiota in terms of food safety. The objective of this study was to compare the microbiota, inflammatory responses, and zootechnical parameters of broiler chickens not exposed to Campylobacter jejuni with those exposed either early at 6 days old or at the age commercial broiler chicken flocks are frequently observed to become colonized at 20 days old. Results Birds infected with Campylobacter at 20 days became cecal colonized within 2 days of exposure, whereas birds infected at 6 days of age did not show complete colonization of the sample cohort until 9 days post-infection. All birds sampled thereafter were colonized until the end of the study at 35 days (mean 6.1 log10 CFU per g of cecal contents). The cecal microbiota of birds infected with Campylobacter were significantly different to age-matched non-infected controls at 2 days post-infection, but generally, the composition of the cecal microbiota were more affected by bird age as the time post infection increased. The effects of Campylobacter colonization on the cecal microbiota were associated with reductions in the relative abundance of OTUs within the taxonomic family Lactobacillaceae and the Clostridium cluster XIVa. Specific members of the Lachnospiraceae and Ruminococcaceae families exhibit transient shifts in microbial community populations dependent upon the age at which the birds become colonized by C. jejuni. Analysis of ileal and cecal chemokine/cytokine gene expression revealed increases in IL-6, IL-17A, and Il-17F consistent with a Th17 response, but the persistence of the response was dependent on the stage/time of C. jejuni colonization that coincide with significant reductions in the abundance of Clostridium cluster XIVa. Conclusions This study combines microbiome data, cytokine/chemokine gene expression with intestinal villus, and crypt measurements to compare chickens colonized early or late in the rearing cycle to provide insights into the process and outcomes of Campylobacter colonization. Early colonization results in a transient growth rate reduction and pro-inflammatory response but persistent modification of the cecal microbiota. Late colonization produces pro-inflammatory responses with changes in the cecal microbiota that will endure in market-ready chickens.

The possibility of ultraviolet (UV) photooxidation of cypermethrin generating more toxic intermediates or isomers demands that studies that look at the effects of cypermethrin and UV irradiation under a coexposure scenario be carried out. In this study, juvenile African catfish (Clarias gariepinus) were exposed to 50 µg/L cypermethrin, 100 µg/L cypermethrin, UV, 50 µg/L cypermethrin + UV or 100 µg/L cypermethrin + UV, in a static renewal for 3 weeks. The control fish were maintained in uncontaminated water, and not exposed to UV radiation. After the exposure duration, the fish were killed, and the activities of acid phosphatase, alkaline phosphatase, amylase, protease, and lipase were determined in the liver or intestinal homogenates. Also, the histopathology of some sections of the intestine was performed. The results showed that the activities of the enzymes decreased significantly following exposure to cypermethrin while there was no change in the activities of the enzymes due to UV irradiation alone. The histopathological analyses indicated that exposure to cypermethrin caused alterations in the histoarchitecture of the fish such as severe erosion of the mucosa layer, faded lamina propria, and disintegration of the muscle layer. The exposure of fish to both cypermethrin and UV irradiation caused significant decrease in the activities of the enzymes. This could be an indication that UV irradiation has the tendency to potentiate cypermethrin‐induced toxicity in fish. Research Highlights: The exposure of C. gariepinus to cypermethrin caused significant decrease in the activities of important metabolic enzymes, and altered the histoarchitecture of the intestine. UV exposure potentiated cypermethrin‐induced toxic effects in the fish. [ABSTRACT FROM AUTHOR]

This study was designed to determine the effect of fishmeal (FM) replacement with soybean meal (SBM) in the diet of tilapia (Oreochromis niloticus). Growth, digestive enzyme activity, antioxidation, and gut histomorphology were assessed in the fish fed with five different formulated diets that increasingly replaced FM. The SBM0 contained 100% FM, followed by 25% (SBM25), 50% (SBM50), 75% (SBM75), and 100% (SBM100). Juvenile tilapia having weight and length of 6.6 ± 0.1 g and 5.4 ± 0.2 cm, respectively, were randomly divided into five treatment groups. Each group had 40 individual fish and fed to visual satiation for 90 days. Body weight gain and specific growth rate in fish fed with 25–75% SBM increased significantly (P < 0.01) compared with those in fish fed with SBM100. Fish having the same weight fed with diets SBM50, SBM75, and SBM100 showed a significantly (P < 0.01) longer intestine compared with those fed with SBM0 and SBM25. Villus height of the stomach and intestine was significantly (P < 0.01) greater in the fish fed with the diets SBM0, SBM25, and SBM50 compared with SBM75 and SBM100. Muscular thickness was inversely related with the increasing villus height. Protease activity increased significantly (P < 0.01) in the stomach, anterior intestine, and posterior intestine of fish fed with SBM0 compared with SBM100. In the stomach and anterior and posterior segments of the intestine, significantly (P < 0.01) higher lipase activity was observed in fish fed with the diets SBM0 and SBM25 compared with diet SBM100. In the stomach, anterior intestine, and posterior intestine, amylase activity was also significantly (P < 0.01) greater in SBM0 compared with SBM100. The antioxidant enzymes including superoxide dismutase and catalase of the liver were significantly (P < 0.01) higher in fish fed SBM100 compared with SBM0. These results suggest that the replacement of FM up to 75% with SBM could be possible considering the growth performances, gut health, and activities of digestive enzymes and antioxidant enzymes in O. niloticus. [ABSTRACT FROM AUTHOR]

A study was carried out to evaluate the effect of in ovo feeding during earlyembryonic life with either vitamin C or glucose on hatchability, post hatch performance, carcass traits and gut histology. Two sets of Dandrawi fertile eggs (400 eggs each with average weight 51.1± 0.2g) were used in two separate trials. On d 14 of incubation, eggs of the first set (Trial 1) were examined and those containing live embryos were divided equally into 4 treatments (100 eggs/ treatment) and injected in the amnion as follows: T1 (negative control, no injection); T2 (positive control, injected with 0.1ml saline solution 0.9g/L); T3 (injected with 0.1ml 2.5 % water solved vitamin C); T4 (injected with 0.1ml 5% water solved vitamin C). Eggs of Trial II: T1 (negative control, no injection); T2 (positive control, injected with 0.1ml saline solution 0.9g/L); T3 (injected with 0.1ml 5 % water solved glucose); T4 (injected with 0.1ml 10% water solved glucose). Hatched chicks from each trial were allocated into 3 replicates/ treatment and brooded till 10 weeks old. Performance of chicks of T4 (Trial 1) hatched from the eggs injected with 5% vitamin C showed significant (P<.01) improvement in BW, BWG, FCR and scored the lowest percent of mortality. However; measurements of carcass traits showed no significant differences among treatments. Furthermore, blood parameters were all within normal physiological values. Histological examination of the gut revealed positive influence (P<.01) of 5% vitamin C injection level on height and width of duodenum villi. Results of the second trial showed significant (P<.01) enhancement in performance of the chicks hatched from the eggs injected with 10% glucose. Also, histological evaluation of the same group scored the highest (P<.01) values of duodenum villi height and width. In conclusion, in ovo injection at d 18 of incubation with either 0.1 ml 5% vitamin C or 0.1ml 10% glucose improved post hatch Dandarawi chicks' performance and gut histological traits related to nutrient absorption. [ABSTRACT FROM AUTHOR]

To develop specific recommendations on the feeding strategies for farmed lumpfish, four duplicate groups (n = 70; N = 280) of lumpfish with a mean ± SD start weight of 30.4 ± 5.3 g were distributed among eight sea cages (5 × 5 × 5 m) each stocked with 220 one year old Atlantic salmon with a mean (± SD) weight of 1485.9 ± 213.2 g. The fish were fed either pelleted feed at 3% BW−1 or with feed blocks at 1.5%, 2% and 3% BW−1 respectively for 66 days. There were clear differences in growth performance between the four treatment groups with lumpfish fed with pelleted feed attaining the highest weight gain. There were only minor histopathological changes observed between the dietary treatments with mainly mild focal and multifocal inflammation observed in sampled tissues. There were no significant differences in liver vacuolisation between the dietary groups and baseline samples with most of the livers evaluated appeared to be vacuolized within what is regarded as normal range for all four treatment groups. Only minor differences in welfare score between the four treatment groups were found. The incidence of cataracts varied between the treatment groups and was correlated to differences observed in growth between the four groups. Lumpfish fed once daily from automatic feeders with pelleted feed had the highest incidence and severity of cataracts. This study suggests that feeding lumpfish with moderate amounts of feed blocks (≤ 2% BW−1) may be advantageous for maintaining slow growth and good welfare in salmon cages, and this should be further tested in large scale studies in commercial salmon farms. • We assessed growth, cataract development, welfare score and gut histopathology in lumpfish fed either pelleted feed or with feed blocks. • Lumpfish fed with pelleted feed attaining the highest weight gain. • Lumpfish fed with pelleted feed had the highest incidence and severity of cataracts. • Only minor histopathological changes observed between the dietary treatments. • Feeding lumpfish with moderate amounts of feed blocks (≤ 2% B−1) in salmon cages is recommended. [ABSTRACT FROM AUTHOR]

Fishmeal and fish oil substitution in aquafeeds might have adverse effects on fish growth and health, mainly in carnivorous species, such as Mediterranean yellowtail ( Seriola dumerili ). Mediterranean yellowtail shows great potential as an alternative aquaculture species due to its fast growth and high price on the market, but the need for high-quality protein and fatty acid content in its diets is limiting its production. In order to improve the sustainability of its production, this study was conducted with 360 fish of 35 g to evaluate the effects on fish growth and health. Six diets were used: one control diet without replacement, three with FM replacement (FM66, FM33, and FM0) (33%, 66%, and 100% FM replacement), and two with FO replacement (FO50 and FO0) (50% and 100% FO replacement). The substitution of FM was with vegetable (VM) (corn gluten) and animal (AM) (krill and meat meal) meals. The reductions in FM and FO of up to 33 and 0%, respectively, did not affect the growth and survival of S. dumerili at the intestinal morphology level, except for the anterior intestine regarding the lower villi length and width and the posterior intestine regarding the lower width of the lamina propria. On the other hand, the substitution of fish ingredients in the diet affects liver morphology, indicating alterations in the major diameter of hepatocytes or their nuclei. Finally, diet did not affect the gut microbiota with respect to the control, but significant differences were found in alpha and beta diversity when FO and FM microbiota were compared. A 66% FM replacement and total FO replacement would be possible without causing major alterations in the fish.

This study was designed to test the effect of a herbal product, Aquapro®, on the growth performance and gut morphology of dusky kob, Argyrosomus japonicus (Temminck & Schlegel, 1843) in a 49-day feeding trial. Four diets, containing Aquapro® at 0 (Aqua0), 50 (Aqua50), 100 (Aqua100), and 150 (Aqua150) g.kg-1 dry matter (DM) were formulated. Forty-five fish (14.44 ± 0.27 g) were randomly distributed into each of 12 experimental tanks. Each dietary treatment was randomly allocated to three tanks and offered to fish at 2.8 % body weight. Ten fish from each tank were randomly sampled weekly for length and weight measurements. At termination, three fish from each tank were sampled for distal intestinal tissues for histology preparation. A non-significant (P > 0.05) interaction between the diets and the fish age (weeks) on both the weight and caudal length of the fish was observed. The fish weight decreased significantly with an increase in Aquapro® inclusion in the diets beyond 100 g.kg-1. The Aqua150 diet produced the least weight gain of 24.57 ± 2.44 g. Aquapro® inclusion in the diets did not cause any gut morphological alterations in the fish. In conclusion, Aquapro® product, up to 100 g.kg-1 kob diet does not negatively affect juvenile dusky kob growth and all the tested inclusion levels did not cause gut inflammation, thereby suggesting uninterrupted nutrient absorption. [ABSTRACT FROM AUTHOR]

Abstract Three duplicate groups of individually tagged lumpfish (mean initial weight: 22.3 ± 2.5 g) were fed either daily (7DW); four days per week (4DW) or three days per week (3DW) at a feeding rate of 2% body weight day−1 for a period of 126 days. There were significant differences in growth rates between the groups with the 7DW fish having the highest growth rates. Cataract prevalence was 53% lower in the 3DW group compared to the 7DW group. Histological examination showed that in some individuals in all three groups there was moderate expansion of the lamina propria in the mid and hind gut regions of the intestine with tissue most likely to represent fibrous tissue with scattered leucocytes. The severity of inflammation appeared to increase the more frequent the fish were fed with the 7DW fish having the highest inflammation score in these tissues. Feeding fish daily also resulted in higher levels of liver vacuolisation and chronic inflammation of the lamina propria in the mid and hind gut region of the intestines. Results from the present study show that restricted feeding regimes can be used to control growth and improve gut and eye health in lumpfish. Highlights • We assessed growth, cataract development and gut histopathology in lumpfish feed 7, 4 and 3 days per week (DW). • Growth and cataract prevalence was lowest in the 3DW group. • Liver vacuolisation and chronic inflammation in the gut was higher in the 7DW group. [ABSTRACT FROM AUTHOR]

Early weaned rabbits should be fed using a milk replacer in order to survive. Therefore, a rabbit milk replacer (RMR) was developed and compared with a kitten milk replacer (KMR®: KMR) and a mammal milk replacer (Zoologic® Milk matrix 30/52: MMR). Thirty-six native crossbred rabbits aged 18 days were divided into three experimental groups (six replicates/group, two rabbits/replicate), fed RMR, KMR or MMR daily until they were 36 days old and euthanized at 38 days, while a complete pelleted diet and water were provided ad libitum. No statistically significant differences were observed in growth performance parameters, water intake, faecal weight, nutrient digestibility, internal organ weight, caecal pH, caecal cellulose activity, number of faecal pellets and amount of crude protein intake (p > 0.05). Caecal amylase activity in the KMR group and caecal protease activity in the RMR group were higher than in the MMR group (p < 0.05). The villus height and crypt depth of the MMR group were greater than in the RMR and KMR group (p < 0.05). In conclusion, it is possible to feed RMR to early weaning rabbits without serious adverse effects. However, probiotics and/or prebiotics should be supplemented in milk replacers and their benefits studied.

Changing trends in fish feed formulation, with progressively higher inclusion levels of plant ingredients, are invariably introducing more fibre despite the fact that this component cannot be utilized by most fish. The effects of increasing insoluble dietary fibre level on growth, nutrient utilisation, blood parameters and gut health in European sea bass ( Dicentrarchus labrax L.) were studied over a period of 117 days. Moreover, investigation on digesta transit time through gastrointestinal evacuation pattern and digesta characteristics (moisture of digesta) were studied. Five isoproteic diets were formulated to contain increasing insoluble fibre levels, neutral detergent fibre, NDF (7.2, 8.9, 11.5, 13.1 and 15.5%) derived by the inclusion of sunflower hulls and soybean hulls. No significant differences due to fibre inclusion levels were observed in final body weight, specific growth rate, feed intake, feed conversion rate, protein and lipid efficiency. No significant differences in serum total protein, glucose, triglycerides, alkaline phosphatase and inorganic phosphorous were found. All the histological sections showed normal intestinal architecture, and inflammatory and/or degenerative changes were not present in any histological section from all subjects examined. The investigation into gastrointestinal evacuation pattern revealed no significant differences between treatments, however higher dietary fibre levels seem to increase the time required to empty the stomach while the time required to empty 90% of the hindgut content was similar in all the treatments: around 46–47 h. No differences were found between diets in the moisture content of digesta along the digestive tracts. We can conclude that the different insoluble fibre levels tested in this trial have no effects on overall performances and feed efficiency in European sea bass. Results from blood biochemistry profile and histology confirm good nutritional and health status of fish under all feeding treatments. The inclusion of fibre had no influence on digesta transit time. In formulation of feed for the on-growing of European sea bass insoluble fibre derived from sunflower hulls and soybean hulls can be included at a level of up to 15.5%. [ABSTRACT FROM AUTHOR]

Diets offered to lactating and weaned piglets are the most expensive diets within pig production; however, the effect of these diets on lifetime pig performance is inconsistent. The objective of the current study was to investigate the impact of creep feed consumption during lactation and different starter diet allowances on piglets' gut structure and lifetime growth performance. In total, 320 pigs and 80 pigs (Landrace × Large White) were used after weaning in a 2 × 2 factorial arrangement to study growth performance and gut structure, respectively. At weaning, piglets that ate creep feed and piglets that were not offered creep feed during lactation were allocated to 2 kg/pig [low level (LL)] or 6 kg/pig [high level (HL)] of starter 1 diet (16.5 MJ DE/kg, 22.5% CP, and 1.7% total Lys) allowance. At weaning and at 1 and 3 wk after weaning, 8 piglets per treatment were sacrificed, and their small intestine morphology was evaluated (villus height and crypt depth). Piglets that ate creep feed had increased feed intake during the first week after weaning (P < 0.05), but no effect of creep feed intake was observed on piglets growth or gut structure during the postweaning period (both P > 0.05). Piglets that were fed HL after weaning had higher ADG and BW from weaning to 16 wk after weaning (both P < 0.05) and had lower feed conversion ratio (FCR) from weaning to 6 wk after weaning (P < 0.05). Piglets fed HL after weaning also had higher villi height and greater crypt depth than LL piglets at 3 wk after weaning (both P < 0.05). Creep feed consumption during lactation increases feed intake early after weaning, suggesting an improved capacity of piglets to cope with weaning, but did not influence their growth performance. Offering piglets 6 kg of starter diet enhances piglets' growth performance during the growing and finishing phase, probably by improving gut structure after weaning. [ABSTRACT FROM AUTHOR]

Abstract: Three duplicate groups of individually tagged lumpfish (mean initial weight: 20.0 ± 4.0 g) were fed three commercially available diets (A, B and C) for a period of 147 days. There were significant differences in growth rates between the groups with fish fed diet A having the highest growth rates whilst fish fed diet C achieved the lowest growth. Lumpfish fed diets A and B had lower prevalence and severity of cataracts compared with fish fed diet C, suggesting a possible dietary effect on cataract, alone or in combination with other environmental factors. There was a significant difference in the degree of liver vacuolization between the three dietary treatments at the end of the study period with fish fed diets A and B showing moderate to severe vacuolization compared with liver tissue from fish fed diet C, which had milder vacuolizations. There was little or no inflammation in pyloric caeca, midgut and hindgut and similarly for epithelial necrosis or vacuolization for all three dietary treatments at the end of the study. Fish fed diet A had the longest intestinal folds whilst fish fed diet C had the shortest. [ABSTRACT FROM AUTHOR]

The present study was carried out to evaluate growth, gut histology and gut bacterial community of gilthead sea bream ( Sparus aurata ) fed with increasing dietary soybean meal (SBM) levels in a low fishmeal (FM) based diet, in comparison with a control diet. Five isoproteic and isolipidic experimental diets were formulated to contain increasing levels of SBM (0, 100, 200, and 300 g kg −1 named S0, S10, S20 and S30, respectively) with 150 g kg −1 of FM, and one control diet (C) without SBM and containing 350 g kg −1 of FM. Sixty sea bream (initial body weight 75.9 ± 1.9 g, n = 900) per tank were reared in a recirculation system at 23.0 ± 1.0 °C and fed to satiation. The trial was run in triplicate and lasted 100 days. At the end of the trial fish fed the S30 diet showed a higher ( P ≤ 0.05) specific growth rate (SGR) compared to S0 (SGR, 1.17 ± 0.03, 1.20 ± 0.01, 1.22 ± 0.01, 1.25 ± 0.01 and 1.21 ± 0.04 for S0, S10, S20, S30 and C, respectively), and a higher feed intake (FI) compared to S0, S10 and S20. Sea bream fed the C diet had a higher ( P ≤ 0.05) FI compared to S0 (FI, 1.40 ± 0.01, 1.45 ± 0.01, 1.44 ± 0.03, 1.51 ± 0.03 and 1.46 ± 0.02 for S0, S10, S20, S30 and C, respectively). No significant differences in feed conversion rate, protein efficiency ratio, gross protein efficiency and gross lipid efficiency among the treatments were detected. No specific histopathological changes indicative of soy-induced enteritis were observed in the intestine of any fish examined. Gut bacterial community of the distal intestine content was analyzed by Next-Generation Sequencing. At the phylum level, the gut bacterial community was dominated by Firmicutes (relative abundance 71%), while the most represented family was Lactobacillaceae (26%). Even if no significant differences ( P ≤ 0.05) in the gut bacterial community α and β-diversity according to the different diets were detected, Cyanobacteria and Lactobacillaceae progressively increased from diet C to diet S30. In conclusion results of growth, nutrient utilization, gut histology and gut bacterial community indicate that SBM can be successfully incorporated up to a level of 300 g kg −1 with the inclusion of 150 g kg −1 of FM, without any deleterious effects on growth, protein utilization and gut health during the on-growing of sea bream. [ABSTRACT FROM AUTHOR]

The aim of our experiment was to study how synbiotics are able to deal with the problems of post-weaning piglets. Lactobacillus plantarum - BiocenolTM LP96 (CCM 7512), Lactobacillus fermentum - BiocenolTM LF99 (CCM 7514) and flaxseed (rich in n-3 polyunsaturated fatty acids) were administered to 36 conventional piglets from a problematic breed with confirmed presence of enterotoxigenic Escherichia coli and Coronavirus. The experimental piglets were supplied with probiotic cheeses and crushed flax-seed in the period starting 10 days before weaning and lasting up to 14 days post-weaning. Piglets in the control group were supplied only control cheese. The impact of such additives on the release of lactate dehydrogenase (LDH; spectroscopic and electrophoretic assay), alteration of immunity (index of metabolic activity), jejunum histology (light microscopy), and health of conventional piglets from a problematic breed (monitoring of hematology, consistency and moisture of feces and body temperature) were examined. We found significant decrease in LDH leakage in the blood serum and tissue extracts, indicating better cell membrane integrity in the individual organs of animals. Probiotics and flaxseed applied together seem to be a good source of nutrients to improve the immune status and the integrity of jejunum mucosa during infection. © 2015 Japanese Society of Animal Science [ABSTRACT FROM AUTHOR]

The gut microbiomes of fish play important roles in host development, digestion and health. Evidence suggests that abiotic factors, such as diet and rearing temperature, could affect fish gut microbiota. In this study, the effect of dietary short-chain fructooligosaccharides (sc FOS) on turbot intestinal health, microbiota and digestive enzymes was investigated at two rearing temperatures: 15 and 20 °C. Four practical diets were supplemented with sc FOS at 0, 5, 10 and 20 g kg−1. sc FOS did not affect fish performance. PCR- DGGE did not show differences in bacterial profiles between dietary treatments; however, the number of operational taxonomic units, richness and diversity were higher at 20 °C. Enzyme activities in the foregut were not affected by rearing temperature, while in the hindgut, enzyme activities were higher at 15 °C. Total alkaline protease, α-amylase and lipase activities in the foregut were higher in fish fed 20 g kg−1 sc FOS. Prebiotic supplementation had no effect on hindgut α-amylase activity, while lipase activity of fish reared at 20 °C was higher in fish fed diet with 5 g kg−1 sc FOS. No differences were observed in intestinal morphology. This was the first study to simultaneously evaluate the effect of dietary prebiotic level and rearing temperature on fish intestinal microbiota and health. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the effects of short-chain fructooligosaccharides (scFOS), xylooligosaccharides (XOS) and galactooligosaccharides (GOS) on immune and hepatic oxidative status, and gut morphology of white sea bream juveniles. Four diets were formulated: a control diet with fish meal (FM) and plant feedstuffs (PF) (30FM:70PF) and three test diets similar to the control but supplemented with 1% of scFOS, XOS or GOS. Dietary prebiotic incorporation did not affect total blood cell counts, hematocrit, hemoglobin, red blood indices or differential white blood cell counts. Fish fed GOS had lower ACH50 and nitric oxide than fish fed control diet. XOS enhanced immune status through the increase in alternative complement pathway (ACH50), lysozyme and total immunoglobulin. The higher activity of glucose 6-phosphate dehydrogenase in fish fed FOS compared to the other dietary groups was the only related antioxidant enzyme affected by prebiotics in the liver. GOS ameliorated the precocious adverse effects of PF based diet on gut histomorphology, as denoted by the lower incidence of histological alterations in fish fed GOS for 15 days. In conclusion, XOS and GOS at 1% might have potential to be used as prebiotics in white sea bream juveniles. [ABSTRACT FROM AUTHOR]

The effects of dietary short chain fructooligosaccharides (scFOS) incorporation on hematology, fish immune status, gut microbiota composition, digestive enzymes activities, and gut morphology, was evaluated in gilthead sea bream ( Sparus aurata ) juveniles reared at 18 °C and 25 °C. For that purpose, fish with 32 g were fed diets including 0, 0.1, 0.25 and 0.5% scFOS during 8 weeks. Overall, scFOS had only minor effects on gilthead sea bream immune status. Lymphocytes decreased in fish fed the 0.1% scFOS diet. Fish fed the 0.5% scFOS diet presented increased nitric oxide (NO) production, while total immunoglobulins (Ig) dropped in those fish, but only in the ones reared at 25 °C. Red blood cells, hemoglobin, bactericidal activity and NO were higher at 25 °C, whereas total white blood cells, circulating thrombocytes, monocytes and neutrophils were higher at 18 °C. In fish fed scFOS, lymphocytes were higher at 18 °C. Total Ig were also higher at 18 °C but only in fish fed 0.1% and 0.5% scFOS diets. No differences in gut bacterial profiles were detected by PCR-DGGE (polymerase chain reaction denaturing gradient gel electrophoresis) between dietary treatments. However, group's similarity was higher at 25 °C. Digestive enzymes activities were higher at 25 °C but were unaffected by prebiotics incorporation. Gut morphology was also unaffected by dietary prebiotic incorporation. Overall, gut microbiota composition, digestive enzymes activities and immunity parameters were affected by rearing temperature whereas dietary scFOS incorporation had only minor effects on these parameters. In conclusion, at the tested levels scFOS does not seem worthy of including it in gilthead sea bream juveniles diets. [ABSTRACT FROM AUTHOR]

The present study evaluated the effects of magnesium (Mg) on growth, antioxidant capacity, intestinal morphology and ammonia nitrogen resistance in juvenile oriental river prawn, Macrobrachium nipponense. Six semipurified diets (crude protein 401.1 g kg−1 diet; crude lipid 88.7 g kg−1 diet) containing Mg levels of 1.1, 1.4, 1.6, 2.1, 2.8 or 4.5 g kg−1 were formulated. A total of 1080 healthy juvenile prawns (0.151 ± 0.003 g) were randomly stocked into eighteen 300 L tanks (100 × 80 × 60 cm), each tank with 60 prawns. Each experimental diet was fed to prawns in triplicate twice daily (08:00 and 17:00) for eight weeks. After the feeding trial, 20 prawns from each tank were challenged with 37 mg/L ammonia nitrogen for 96 h, and the hemolymph, hepatopancreas and muscle of the rest of the prawns were collected. Final biomass was higher in prawns fed diets containing 1.6 and 2.1 g Mg kg−1 compared with those fed the diet with 1.1 g kg−1. Higher alkaline phosphatase (ALP) activity was obtained in the serum of prawns fed the 2.1 and 2.8 g Mg kg−1 diets. The highest activities of hepatopancreas superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and total antioxidant capacity (T-AOC) were observed in prawns fed 1.6–2.8 g Mg kg−1 of feed, and the lowest hepatopancreas malondialdehyde (MDA) concentrations and serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities were found in these treatment groups. Similarly, the prawns fed diets with 1.6 and 2.1 g Mg kg−1 had significantly lower MDA concentrations and cumulative mortality and higher antioxidant enzyme activities after ammonia nitrogen exposure. The intestinal epithelial cells were closely attached to the membrane in prawns fed the 2.1 g Mg kg−1 diet, but they were partly detached in those fed the 1.1 and 4.5 g Mg kg−1 diets. The minimum dietary Mg supplementations of juvenile M. nipponense were determined to be 1.6, 1.9, 2.0 and 2.2 g kg−1 feed, respectively, using broken-line regression analysis based on the final biomass, SOD, ALT and ALP. • Optimal dietary magnesium (Mg) enhanced antioxidant capacity and health of juvenile Macrobrachium nipponense. • After ammonia stress, prawns fed on 1.6 and 2.1 g Mg kg−1 had lower cumulative mortality and higher antioxidant capacity. • Dietary supplementation of 1.6–2.2 g Mg kg−1 feed is recommended to promote the growth and well-being of juvenile prawns. [ABSTRACT FROM AUTHOR]

The effects of feeding Artemia nauplii enriched with or without poly-β-hydroxybutyrate ( PHB) and/or highly unsaturated fatty acids ( HUFA) on Siberian sturgeon ( Acipenser baerii) larvae were investigated. Feeding larvae with PHB-enriched nauplii ( PHB, PHB + HUFA) decreased the growth performance of the larvae. PHB affected the body composition by increasing the lipid content of the whole body and decreasing total saturated, monoenoic, n3, n6 and decosahexanoeic acid ( DHA) in the larvae, indicating that the PHB addition affected lipid metabolism. A high activity of pepsin was observed in the digestive extracts of PHB treatments ( PHB, PHB + HUFA), while PHB suppressed amylase activity in the intestine of the larvae. Based on molecular analysis, PHB changed the microbial community in the distal intestine of the larvae. The highest counts of goblet cells were observed in the HUFA-containing treatments ( HUFA, PHB + HUFA), indicating that HUFA addition may improve the mucosal barrier defence system. The overall quality of the larvae was evaluated by exposing them to different salinities and ammonia stress levels. PHB decreased survival rates in these challenges. Our results show that optimal PHB doses for bio-encapsulation into Artemia remain to be determined for further application at the earliest larval stages of sturgeon. [ABSTRACT FROM AUTHOR]

A 60-day feeding trial was conducted to assess the effects of dietary Saccharomyces cerevisiae -originated free nucleotides on growth, innate immunity, intestinal histomorphometry and disease resistance in Nile tilapia, Oreochromis niloticus (average initial weight of 7.85 g). Five diets (treatments) were prepared: negative control diet (NCD) - basal diet without additives; positive control diet (PCD) - basal diet supplemented with a commercial nucleotide-based additive at 170 ppm; and three experimental diets, N170, N320 and N470, supplemented with S. cerevisiae -originated free nucleotides at 170, 320 and 470 ppm, respectively. There were no significant differences in production parameters after the trial period. Nevertheless, the complement hemolytic activity was higher in fish subjected to the three experimental diets, while serum lysozyme concentration was higher in the N470 group compared with both controls. Intestinal villi height and density were greater in fish fed the N470 diet compared with the NCD group. In addition, fish receiving the three experimental diets showed higher absorption surface area magnification ratio, with the greatest values being observed in the N470 group. Lastly, the highest survival rate following Aeromonas hydrophila challenge was recorded in the N470 group. Taken together, the present findings indicate that supplementation of feed with S. cerevisiae -originated free nucleotides at 470 ppm improves non-specific immune responses and intestinal microstructure morphology as well as increases survival rate after bacterial infection in Nile tilapia. Therefore, this blend of natural nucleotides has the potential of being used as an alternative to antimicrobials when included as an additive in aquaculture feeds. • Diets supplemented with Saccharomyces cerevisiae -originated free nucleotides were examined in Nile tilapia. • S. cerevisiae -originated free nucleotides promoted improvements in immunity and intestinal morphology in Nile tilapia. • Diets supplemented with S. cerevisiae -originated free nucleotides increased the survival rate after bacterial infection. [ABSTRACT FROM AUTHOR]

Abstract: The main aim of the current experiment was to assess the potential of dietary orange peel extract (OPE) and lemon peel extract (LPE) as promoters of broiler resistance to high ambient temperature. The experiment was conducted as a 2×3 factorial arrangement of treatments with 2 levels of OPE (0 and 200mg/kg feed) and 3 levels of LPE (0, 200, and 400mg/kg feed). At d 25, a total of 288 Ross 308 broilers were randomly assigned to 6 dietary treatments with 4 replicates of 12 broiler chickens each. The temperature was increased to 34°C with 50% relative humidity for 5h daily starting from d 28 until d 38. At the end of the trial (d 38), 4 male broiler chickens per pen were sampled for determination of serum components and variables of intestinal morphology. Dietary OPE and LPE did not affect weight gain, feed intake, and feed conversion ratio of broiler chickens. The inclusion of 200mg/kg OPE increased serum total protein, but reduced serum lactate dehydrogenase and creatine phosphokinase activity in broiler chickens (P<0.05). Lemon peel extract supplementation decreased the activity of lactate dehydrogenase quadratically (P=0.039) and creatine phosphokinase linearly (P=0.037). No differences in the other blood characteristics and intestinal traits were observed with the exception of muscularis thickness of duodenum, which was reduced when LPE was added to the diet (linear, P=0.011). These results indicate that OPE, LPE, and their combination might modify some blood components and the proximal intestinal morphology, but without beneficial effect on growth performance of broiler chickens under hot conditions. [Copyright &y& Elsevier]

Abstract: This work tested the effect of replacing zinc bacitracin with a blend of caproic and caprylic acids in a diet including colistin on growth performance, mortality, gut histology and development of intestinal lymphoid tissues in rabbits experimentally infected with Escherichia coli and Clostridium perfringens. Three experimental diets were formulated: a control non-medicated diet (diet C), diet C medicated with 150mg zinc bacitracin and 120mgcolistin/kg (diet B) and diet C supplemented with a 4-g mixture of the acids and 120mgcolistin/kg (diet A). Forty rabbits weaned at 28days of age and housed individually were assigned to each diet. At 35days of age, rabbits were orally infected with 109 cfu of E. coli and 109 cfu of C. perfringens. At 35 and 56days of age, five rabbits per diet and age were slaughtered to assess caecal traits, jejunal histology and follicular development in the caudal ileal Peyer''s patch and the appendix. No significant differences were reported on growth performance. Mortality rate reached 60.0% for control rabbits whereas no mortality occurred in rabbits fed the supplemented diets. Caecal pH was not influenced by diet but was lower at 56 than at 35days (6.20 vs. 6.49, P<0.001). No differences were detected on villus height of control rabbits between 35 and 56days of age (average height of 597μm) but villi of rabbits fed diets B and A were, respectively, 19 and 34% (P<0.001) longer at 56days than at 35days. The average follicle area in the Peyer''s patch (81,900μm2 vs. 56,800μm2, P<0.001) and in the appendix (116,000μm2 vs. 56,900μm2, P<0.001) increased after the infection. Besides, average follicle area of the Peyer''s patch was influenced by diet (78,983μm2 vs. 69,632μm2 vs. 59,457μm2, P=0.011, for diets C, B and A, respectively). No significant effect of treatments was detected on the number of follicles of the appendix (37.2 follicles on average). To conclude, the substitution of caproic and caprylic acids for zinc bacitracin in a diet including colistin increased jejunal villus height and reduced follicle hypertrophy of the caudal ileal Peyer''s patch in growing rabbits experimentally infected with C. perfringens A and E. coli O103. The dietary combination of colistin with both zinc bacitracin and the blend of esterified caproic and caprylic acids prevented the rise of fattening mortality, even after the infection. However, the effect of including medium-chain organic acids in a diet free of medication on challenged rabbit health is yet to be elucidated. [Copyright &y& Elsevier]

The effect of metabolic efficiency and associated gut characteristics of laying hens on the variability of transfer of dietary n-3 polyunsaturated fatty acids (PUFA) to the egg was examined in laying hens at 56 wk of age. An empirical energetics model was used to categorize individual hens into energetically efficient or nonefficient treatments based on residual maintenance ME requirement. Birds were then provided a diet containing an extruded flax product as a source of n-3 PUFA for 14 d. Egg traits were determined and yolks collected at 0 d and 14 d for measurement of fatty acid composition and variation in fatty acid levels within hen efficiency class. Gut length and duodenal histomorphometric indices were assessed after the 14-d experimental period. Efficient hens had a 96.01% rate of lay compared with 88.63% in nonefficient hens. After 14 d of feeding, the concentration of n-3 PUFA increased (151.6 vs. 315.8 mg/egg) in the egg yolk whereas n-6 PUFA, saturated fatty acids, and monounsaturated fatty acids were reduced (P < 0.001). Energetic efficiency had no additional effect on these measurements. However, egg yolks from efficient birds had less α-linolenic acid but more docosapentaenoic acid than nonefficient birds, suggesting a greater up-conversion of medium-chain (α-linolenic acid) to long-chain fatty acids (docosapentaenoic acid) in efficient birds. After 14 d, the CV for total n-3 PUFA in egg yolks from efficient hens was lower than that from nonefficient birds (11.1 vs. 21.4), indicating a more uniform level of enrichment. Furthermore, efficient hens had longer duodenal villi (P = 0.02), resulting in a greater absorptive villi surface area (0.13 mm2/villi) than in nonefficient birds (0.10 mm2/villi; P = 0.01). Increased uniformity of n-3 PUFA enrichment of table eggs could be possible through focus on metabolic efficiency and gut absorptive condition in laying hens. [ABSTRACT FROM AUTHOR]

Abstract: A trial on turbot (Psetta maxima) juveniles was undertaken to evaluate the effect of replacing dietary fishmeal (FM) with a complementary mixture of plant proteins (PP) consisting of soybean meal (SBM), wheat gluten meal (WGM) and corn gluten meal (CGM). Four practical diets were formulated to progressively replace 25% (PP25), 39% (PP39), 52% (PP52) and 66% (PP66) of FM protein. Forty animals per tank (initial weight 24.2±4.4g) were randomly distributed into twelve 450-liter square tanks connected to a closed recirculation system (temperature 18±1°C). The diets were tested in triplicate for 77days. Final weight ranged from 126.6g (PP25) to 99.5g (PP66). Voluntary feed intake of group PP66 (55.5gfish−1) was significantly lower than in PP25. Specific growth rate in fish fed diet PP25 (2.14% day−1) was significantly higher than those found both in PP52 (2.01% day−1) and PP66 (1.82% day−1) groups. Feed conversion ratio (FCR) in groups PP25 and PP39 (0.66–0.67) was lower in comparison with those of the other groups (FCR 0.70–0.74). None of the diets affected whole-body composition and hepatosomatic index. Condition factor significantly decreased with increasing dietary PP (2.06, 2.02, 1.97 and 1.91) whereas a significant increase in viscerosomatic index was observed in fish fed PP52 and PP66 (6.70–6.95) in comparison with the other two groups (6.31–6.21). Reduced protein retention was found in groups fed diet PP52 and PP66, with protein efficiency ratio (PER) ranging from 2.71 to 2.63 and gross protein efficiency (GPE) from 40.3 to 40.0, in comparison with the other two groups (PER 2.83 and GPE 45.5–45.8), even though apparent digestibility coefficients were not reduced. Ammonia excretion, (g total ammonia nitrogen 100gproteinintake−1), was significantly higher for group PP25 (3.41) than group PP52 (2.61). Gut histology examined in four different sites of intestine (pyloric caeca, proximal, intermediate and distal intestine) revealed no noticeable differences among fish of the various diet groups. In conclusion, substitution of a mixture of SBM, WGM and CGM for up to 52% of FM protein did not reduce feed intake, and at 39% substitution, turbot maintained optimal growth rate and nutrient utilization. Worsened FCR of fish fed diets containing higher plant protein levels was not associated with a reduced digestibility of ingredients or alterations of gut histology. [Copyright &y& Elsevier]

Abstract: Two experiments were conducted in order to investigate the effect of dietary mannan oligosaccharides (MOS) on gilthead sea bream (Sparus aurata). Experiment I was designed to assess the effect of dietary MOS (0%, 0.2% and 0.4%) on fish fed diets containing fishmeal (FM) as the only protein source. Experiment II was designed to assess the effect of MOS (0% and 0.4%) on fish fed soybean meal (SBM) as a partial replacement of FM (SBM inclusion 31% of diet). After 9weeks feeding on the experimental diets growth parameters, body composition, liver and intestinal histology and intestinal microbial diversity were assessed. The results showed that mean final weight, specific growth rate (SGR), feed conversion ratio (FCR) and protein efficiency ratio (PER) remained unaffected by MOS supplementation of fish fed FM or SBM diets. However, compared to the control group (FM0), condition factor (K) and hepatosomatic index (HSI) were significantly lower in fish fed 0.2% MOS (FM02) and 0.4% MOS (FM04), respectively. These parameters were unaffected in SBM-fed fish. Body proximate composition remained unaffected by MOS supplementation in fish fed either FM or SBM diets (P >0.05). Histological evaluation revealed that MOS had no effect on glycogen deposition in liver and no effect on gross villi morphology in the anterior intestine in either Experiment I or II. However, relative to the control groups (FM0) dietary MOS appeared to improve gross morphological absorptive surface area in the posterior intestine in Experiment I. Electron microscopy revealed that dietary MOS had a pronounced effect at the ultrastructural level in both experiments, as microvilli density and length were elevated in both intestinal regions in fish fed both the FM and SBM based diets. No significant histological differences were found between respective FM0 and SBM0 groups. DGGE analysis revealed that both SBM and MOS affected the intestinal microbial species richness and diversity. However, the effect of dietary MOS on the gastrointestinal microbiota was more pronounced in FM-based diets (Experiment I) as was reflected by increased species richness and diversity and reduced similarity between microbial profiles of the different FM groups. The effect of MOS in Experiment II on SBM-fed fish was marginal, as species richness and diversity remained unaffected and similarity between microbial profiles of the SBM groups and replicates remained high (i.e. >80%). Dietary SBM exerted a greater effect on gut microbiota than dietary MOS. [Copyright &y& Elsevier]

Abstract: Gram positive food-grade bacteria such as lactococci have significant advantages over attenuated pathogens as vaccine delivery vehicles because of their inherently greater safety. Plasmodium falciparum merozoite surface antigen 2 (MSA2) was expressed in recombinant Lactococcus lactis both intracellularly and covalently anchored to the peptidoglycan of the cell wall (MSA2cP). Balb/c mice of different ages were immunised with the MSA2cP expressing L. lactis in a combined oral and nasal immunisation procedure. Serum IgG antibody responses to MSA2 were higher in young adult Balb/c mice compared to old mice and neonates. The elicited serum IgG antibodies reacted with native MSA2 on the surface of P. falciparum merozoites in an immunofluorescence assay. The serum IgG antibody isotypes in young adult mice were mainly IgG1, IgG2a and IgG2b, while IgG3 tended to be higher in old mice. IgA antibodies to MSA2 were also produced in young mice. Enlarged mesenteric lymph nodes, and more prominent lymphoid tissue in the lamina propria of the ileum and lymphoid follicles in the spleen, were observed in mice fed L. lactis. These findings are relevant for developing L. lactis as a vector to deliver vaccines in human populations. [Copyright &y& Elsevier]

Efficacy of Goniothalamin a styryl-pyrone isolated from Goniothalamus wightii Hook.f. and Thoms, against beet armyworm, Spodoptera exigua (Hübner), populations was determined under laboratory condition. The experiments were carried out with concentrations of 5, 10, 15 and 30ppm in an artificial diet and compared with control insects. Laboratory bioassay showed that the goniothalamin had a strong effect on food utilization, moulting and gut histology. The food consumption and conversion of ingested and digested food to body matter decreased with increasing pyrone concentration. The antifeedant activity was also observed in larvae of S. exigua. The treated third instar larvae exhibited mortality in a dose dependent manner. At 5, 10, 15 and 30ppm/insect, the pyrone gave 23%, 45% 63% and 100% mortality respectively. The larvae of S. exigua gained significantly less weight until pupation in the 10 and 15ppm pyrone concentrations. Duration of larval period was also affected after treatment with pyrone. The metamorphosis was delayed with additional moulting (7th instar) after treatment with 10 and 15ppm of goniothalamin, the percentage of larvae successfully moulted into progressive instars was significantly decreased with an increase in pyrone concentrations. The effects of goniothalamin on midgut ultrastructure of third instar larvae of S. exigua were investigated by using light microscopy. Cross sections of the midgut showed that the epithelial cells were destroyed. Significant damage of the midgut epithelium was observed along with lysis. [Copyright &y& Elsevier]