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Background: Aquaculture, traditionally a form of biotechnology, has evolved to integrate innovative biotechnological applications, such as advanced feed formulations, aimed at improving the growth performance and health of farmed fish species. In the present study, the effects of feeding rainbow trout with novel feed formulations were investigated. Fish growth, gut and liver morphology, the concentration of fatty acids in the fillet, and volatile fatty acids in the gut were assessed. The study also validated scenarios from in vivo experiments using a nutrient-based model called FEEDNETICS™. This globally used model serves as a tool for data interpretation and decision support in the context of precision fish farming. Methods: Alternative protein and oil sources, including poultry by-product meal (PBM) and natural algae oil, were explored as sustainable replacements for fishmeal (FM) and fish oil (FO). A 90-day feeding trial was conducted using rainbow trout, comparing two isoproteic, isolipidic and isoenergetic diets. The control diet contained 15% FM, 5% PBM, and 8% FO, while the test diet replaced FM with 15% PBM and 5% feather meal hydrolysate (FMH), and fully substituted FO with VeraMaris® natural algae oil and rapeseed oil. Results: PBM successfully replaced FM protein without negatively affecting feed intake, growth performance or feed utilization in trout. The combination of PBM and natural algae oil was well tolerated by the trout and showed no negative effects on gut health. A detailed analysis of fatty acids in the fillet revealed that PUFAs of the n3 and n6 series were significantly higher in the PBM group than in the FM group. Values of fatty acid-related health indexes, including atherogenicity index, and thrombogenicity index, confirmed the high nutritional value of trout filet, thus representing a healthy product for human. In addition, the predictions using the FEEDNETICS™ indicated that the tested novel alternative formulations are economically viable. The validation of the model for fish growth resulted in a Mean Absolute Percentage Error (MAPE) of 8%. Conclusions: The FEEDNETICS™ application enhances our ability to optimize feeding strategies and improve production efficiency in the aquaculture industry. VeraMaris® algae oil and PBM could serve as viable and sustainable raw materials for fish feed, promoting environmentally friendly aquaculture practices. [ABSTRACT FROM AUTHOR]

Abstract Background Aquaculture, traditionally a form of biotechnology, has evolved to integrate innovative biotechnological applications, such as advanced feed formulations, aimed at improving the growth performance and health of farmed fish species. In the present study, the effects of feeding rainbow trout with novel feed formulations were investigated. Fish growth, gut and liver morphology, the concentration of fatty acids in the fillet, and volatile fatty acids in the gut were assessed. The study also validated scenarios from in vivo experiments using a nutrient-based model called FEEDNETICS™. This globally used model serves as a tool for data interpretation and decision support in the context of precision fish farming. Methods Alternative protein and oil sources, including poultry by-product meal (PBM) and natural algae oil, were explored as sustainable replacements for fishmeal (FM) and fish oil (FO). A 90-day feeding trial was conducted using rainbow trout, comparing two isoproteic, isolipidic and isoenergetic diets. The control diet contained 15% FM, 5% PBM, and 8% FO, while the test diet replaced FM with 15% PBM and 5% feather meal hydrolysate (FMH), and fully substituted FO with VeraMaris® natural algae oil and rapeseed oil. Results PBM successfully replaced FM protein without negatively affecting feed intake, growth performance or feed utilization in trout. The combination of PBM and natural algae oil was well tolerated by the trout and showed no negative effects on gut health. A detailed analysis of fatty acids in the fillet revealed that PUFAs of the n3 and n6 series were significantly higher in the PBM group than in the FM group. Values of fatty acid-related health indexes, including atherogenicity index, and thrombogenicity index, confirmed the high nutritional value of trout filet, thus representing a healthy product for human. In addition, the predictions using the FEEDNETICS™ indicated that the tested novel alternative formulations are economically viable. The validation of the model for fish growth resulted in a Mean Absolute Percentage Error (MAPE) of 8%. Conclusions The FEEDNETICS™ application enhances our ability to optimize feeding strategies and improve production efficiency in the aquaculture industry. VeraMaris® algae oil and PBM could serve as viable and sustainable raw materials for fish feed, promoting environmentally friendly aquaculture practices.

Objective This study investigated the impact of supplementation of protease and organic acid on growth performance and other biological parameters in broilers fed poultry by-product meal (PBM) based diet. Methods Five hundred 1-day-old broiler chicks (Ross 308) were distributed into five treatments with 5 replicates, each pen having 20 birds, and fed each group one of five isocaloric and isonitrogenous diets in two phases: stater phase (1 to 21 days) metabolizable energy (ME) 3000 kcal/kg; crude protein (CP) 22%, and a finisher phase (22 to 35 days) ME 3,200 kcal/kg; CP 19.5%. The dietary treatments were: i) standard broiler ration (Cont); ii) The control diet with 25% of the soybean meal replaced by PBM on an equivalent protein basis (PBM); iii) PBM diet supplemented with 0.5 g/kg of protease (PBMP); iv) PBM diet supplemented with 1 g/kg organic acid (PBMO); and v) PBM diet addition with 0.5 g/kg protease and 1 g/kg organic acid (PBMPO). Results The overall data showed that feed conversion ratio was improved (p

Objective: This study investigated the impact of supplementation of protease and organic acid on growth performance and other biological parameters in broilers fed poultry byproduct meal (PBM) based diet. Methods: Five hundred 1-day-old broiler chicks (Ross 308) were distributed into five treatments with 5 replicates, each pen having 20 birds, and fed each group one of five isocaloric and isonitrogenous diets in two phases: stater phase (1 to 21 days) metabolizable energy (ME) 3000 kcal/kg; crude protein (CP) 22%, and a finisher phase (22 to 35 days) ME 3,200 kcal/kg; CP 19.5%. The dietary treatments were: i) standard broiler ration (Cont); ii) The control diet with 25% of the soybean meal replaced by PBM on an equivalent protein basis (PBM); iii) PBM diet supplemented with 0.5 g/kg of protease (PBMP); iv) PBM diet supplemented with 1 g/kg organic acid (PBMO); and v) PBM diet addition with 0.5 g/kg protease and 1 g/kg organic acid (PBMPO). Results: The overall data showed that feed conversion ratio was improved (p<0.05) in the PBMP group. Apparent CP digestibility was higher (p<0.05) in both Cont and PBMP groups. Jejunal villus height increased (p<0.05) in PBMP and PBMPO groups, while only the PBMO group exhibited a higher (p<0.05) crypt depth. Lipase activity was increased (p<0.05) in the PBMP, PBMO, and PBMPO dietary treatments. However, trypsin activity showed a significant increase (p<0.05) in the PBMP and PBMO groups. Serum biochemistry increased (p<0.05) globulin and total protein levels in the PBMP group. Conclusion: PBM could partially replace the soybean meal with supplementation of either protease or organic acid in broiler diets without impairing overall growth performance. Furthermore, careful optimization must be considered when combining protease and organic acids. [ABSTRACT FROM AUTHOR]

The research focused on development of fish feed utilising poultry by-product meal (PBM) as a substitute for fish meal (FM) and evaluating its shelf life under aerobic packaging conditions. Initially, a basal diet (C) was formulated to meet the nutritional requirements for optimal growth of Tilapia by using FM as the major protein source. After analysing the nutritional composition of PBM, an isoproteinaceous diet (T) was formulated by replacing FM with PBM. The product was packed in HDPE bags and kept at room temperature and analysed for physico chemical and microbial characteristics for 45 days at weekly intervals. Moisture content of both C and T decreased significantly (p<0.01) throughout the storage period and no significant difference (p>0.05) was found between C and T. The TBARS value of both C and T followed an increasing trend. This increase in C was not significant (p<0.01) between 28th and 35th day, and between 42nd and 45th day but that of T increased significantly (p<0.01) throughout the storage period. T consistently displayed the highest TBARS value during storage period. Tyrosine Value (TV) of both C and T also increased during storage and was significant (p<0.01) up to 42nd day of storage. C exhibited the highest TV throughout the storage period. Similarly, total viable count (TVC) of both C and T increased on storage. The increase in TVC for C was not significant (p<0.01) between 21st and 28th days, whereas that of T was significant (p<0.01) throughout the storage period. On 45th day, T exhibited highest count and was significantly different (p<0.01) from C. Throughout the 45-day storage period, no observable coliform count or yeast and mould count was noted in either C or T. The present study indicated that fish feed can be effectively prepared by utilising PBM and can be stored under room temperature up to 45 days. [ABSTRACT FROM AUTHOR]

Our objective was to systematically evaluate the impact of substituting fish meal (FM) with poultry by-product meal (PBM) in fish feed on the growth and hepatic health of loach. Six diets with different levels of PBM (0 %-PBM0, 10 %-PBM10, 30 %-PBM30, 50 %-PBM50, 70 %-PBM70 and 90 %-PBM90 were formulated. After 8 weeks feeding trial, the highest weight gain (WG) was observed in 55 % PBM replacement ratio. Meanwhile, the lowest feed conversion ratio (FCR) were observed in 41.56 % PBM replacement ratio. In addition, dietary PBM induced hepatic oxidative stress including increasing the activity of aminotransferase from PBM0 to PBM50 group, whereas the activity of those enzymes was decreased from PBM50 to PBM90 group. Meanwhile, histological analysis showed that the lipid vacuoles in the liver were increased from PBM0 to PBM50 group, then decreased from PBM50 to PBM90 group (P< 0.05). Moreover, primary bile acid biosynthesis was the only one pathway enriched in top 20 significant pathways by transcriptomic and metabolomic analysis. Specifically, the key bile acid synthesis gene CYP7a1 was down-regulated, while CYP7b1 evinced an up-regulated pattern in PBM50 group compared to PBM0 group. In short, the PBM replacement ratio of up to 50 % in diets was appropriate for rearing loach, while higher PBM replacement ratio resulted in extremely oxidative stress in the liver.

Objective: The carnivorous Yellowtail Snapper Ocyurus chrysurus has the potential for production in aquaculture. However, there is a lack of studies investigating the digestibility of ingredients needed to formulate balanced diets for this species. Methods: The in vitro protein digestibility of fish meal (FM), poultry by‐product meal (PBM), poultry meal (PM), protiblend, canola meal (CM), soybean meal, and wheat gluten was evaluated using the pH‐stat technique. The in vivo digestibility was determined by formulating test diets with a 70:30 ratio of the reference diet and the test ingredients. Result: In terms of in vitro digestibility, FM, PBM, and PM exhibited the highest degree of hydrolysis (DH). Conversely, PBM displayed the lowest apparent digestibility coefficient of protein (ADCprotein) in the in vivo digestibility test. Meanwhile, FM, PM, and CM demonstrated higher values of protein digestibility. Beta regression between ADCprotein and the DH and ash content of the ingredients resulted in a high correlation (R2 = 0.94). Conclusion: The results of the present study indicate that Yellowtail Snapper efficiently digested and absorbed FM, PM, and CM ingredients, which contain a lower content of ash. Impact statementSeveral fish species are overexploited in the production of fish meal, the primary ingredient in fish feed. Therefore, the comprehensive evaluation of potential ingredient substitutes for fish meal is imperative to foster the sustainable development of aquaculture. [ABSTRACT FROM AUTHOR]

Aquaculture has adopted numerous alternatives, including plant-based sources, microbial biomass, and animal by-products, to recognize the importance of reducing fishmeal (FM) use for economic and environmental sustainability. Several studies have been conducted to look into the impact of different animal protein sources, such as meat and bone meal (MBM), feather meal (FeM), blood meal (BM), poultry by-product meal (PBM), and insect meal (IM), as substitutes for FM in the diets of various fish species. Numerous studies have revealed different degrees of favorable results and outcomes. Studies of different fish species with various levels of substitution were reviewed. Moreover, many studies have demonstrated that the development of fish is not significantly impacted by the inclusion of animal meals in their diets at low to moderate levels. Although the use of alternatives such as fishery by-products, insects and terrestrial byproducts has some constraints. However, the utilization of animal-based protein sources generally exhibits positive results with regard to numerous factors, including the variable growth rate, feed conversion ratio, survival rate, and final weight of different fish species. Indeed, certain animal diets also enhanced the blood composition and immune response of certain species. Overall, the perception is that IM is the most advantageous and proactive protein source used in aquaculture. Several studies have shown that PBM and MBM reveal improved results. More research is required to further interpret other factors that influence the dietary incorporation of animal protein sources in aquaculture feeds. [ABSTRACT FROM AUTHOR]

Simple Summary: This study focuses on the use of high-quality and sustainable feed ingredients, derived from circular bioeconomy processes, as major components of new diets for Gilthead sea bream and European sea bass, the most important farmed fish in the Mediterranean basin. In this study, we investigated the effects of replacing dietary plant proteins with insect and poultry by-product meals on the liver health of sea bream and sea bass through histological and biochemical analyses. Four diets were tested, including a control fish meal-free diet, based on plant-derived ingredients, and three other ones, in which 40% of the plant protein was replaced with Hermetia illucens and poultry by-product meals. The results revealed distinct responses to the test diets between sea bream and sea bass, in terms of biometric parameters, lipid metabolism, and liver condition. Sea bream utilized dietary nutrients efficiently, adapting to the test diets in terms of weight gain, physiological well-being, and liver health. Conversely, the test diets led to significant hepatic lipid accumulation in sea bass, resulting in an increased risk to liver health. The liver health of Gilthead sea bream and European sea bass, fed with fish meal-free diets, including various proportions of plant proteins, as well as insect and poultry by-product meals, was investigated through biochemical and histological analyses using a new liver index (LI) formula. Four isoproteic (45% Dry Matter, DM) and isolipidic (20% DM) diets were compared, including a plant-based control diet (CV) and three other test diets, in which 40% of a plant protein-rich ingredient mixture was replaced with meals from Hermetia illucens (H40) or poultry by-product (P40) alone, or in combination (H10P30). The trials lasted 12 and 18 weeks for sea bream and sea bass, respectively. The results obtained thus far highlighted species-specific differences in the physiological response to dietary changes. In sea bream, the biochemical and histological responses suggest favorable physiological and liver health statuses, with higher serum cholesterol (CHO) and triglyceride (TAG) levels, as well as moderate hepatocyte lipid accumulation, with the H10P30 diet compared to the CV (p < 0.05). In sea bass, all diets resulted in elevated serum TAG levels and lipid accumulation in the liver, particularly in fish fed the P40 one (p < 0.05), which resulted in the highest LI, coupled with a higher frequency of severe lipid accumulation, hypertrophy, cord loss, peripheral nuclei displacement, and pyknosis. In conclusion, sea bream adapted well to the test diets, whereas sea bass exhibited altered hepatic lipid metabolism leading to incipient liver steatosis, likely due to the high lipid contents of the diets, including the insect and poultry meals. The LI formula developed in this study proved to be a reliable tool for assessing the effects of dietary changes on the liver health of sea bream and sea bass, consistent with biochemical and histological findings. [ABSTRACT FROM AUTHOR]

Simple Summary: As an excellent but most expensive source of protein, fish meal (FM) is commonly used in 30–60% of the aquafeed for salmon fish species including coho salmon. However, the high cost and unstable supply of FM led it no longer to be considered as a sustainable protein source for aquafeeds. Accordingly, alternative protein sources with low cost and high availability have become a research hotspot in aquafeed for carnivorous species. Poultry by-product meal (PBPM), one of the rendered animal protein sources, can be used as protein substitute of FM in aquafeed due to its economical availability and high protein content and growth promotion effects in comparison to plant proteins. Until now, little information has been available on evaluating the effects of replacing FM by animal proteins including PBPM for coho salmon. In this study, the effects of PBPM instead of FM on growth, muscle composition, and tissue biochemical indexes of coho salmon were investigated. The results showed that the growth performance, feed utilization, muscle composition, serum biochemical indices, and liver antioxidant enzyme activities of coho salmon were negatively affected by high dietary inclusion level of PBPMs, and the optimum substitution level was evaluated based on the specific growth rate (SGR). The present study evaluated the effects of partially substituting fish meal (FM) with poultry by-product meal (PBPM) on the growth, muscle composition, and tissue biochemical parameters of coho salmon (Oncorhynchus kisutch) post-smolts. Five isonitrogenous (7.45% nitrogen) and isoenergetic (18.61 MJ/kg gross energy) experimental diets were made by substituting 0%, 10%, 20%, 40%, and 60% FM protein with PBPM protein, which were designated accordingly as PBPM0 (the control), PBPM10, PBPM20, PBPM40, and PBPM60, respectively. Each diet was fed to triplicates of ten post-smolts (initial individual body weight, 180.13 ± 1.32 g) in three floating cages three times daily (6:50, 11:50, and 16:50) to apparent satiation for 84 days. Both specific growth rate (SGR) and protein efficiency ratio did not differ significantly (p > 0.05) among the control, PBPM10, and PBPM20 groups, which were remarkably (p < 0.05) higher than those of the PBPM40 and PBPM60 groups. Feed conversion ratio varied inversely with SGR. The PBPM replacement had no remarkable effects on the morphological indices and proximal muscle components. The control and PBPM10 groups led to significantly higher muscle contents of leucine, lysine, and methionine than groups of higher PBPM inclusion. The groups of PBPM40 and PBPM60 obtained significantly (p < 0.05) higher serum alanine aminotransferase and aspartate aminotransferase activities than the control and low PBPM inclusion groups. The control group had significantly higher albumin and total cholesterol contents than the groups with PBPM inclusion. The control group had significantly higher triglycerides content than the PBPM60 group. The PBPM60 group had significantly lower contents of high-density lipoprotein, low-density lipoprotein, and total protein than the control and PBPM10 groups. The high PBPM replacement level up to 40% and 60% had adverse effects on hepatic malondialdehyde levels. The catalase and superoxide dismutase activities were not affected by low PBPM inclusion, but significantly decreased in high-PBPM-inclusion groups. Based on broken-line regression analysis of SGR and PER, the optimum dietary PBPM replacing level was evaluated to be 16.63–17.50% of FM protein for coho salmon post-smolts. [ABSTRACT FROM AUTHOR]

Simple Summary: Biogenic amines (BAs) originate from amino acid decarboxylation and are commonly used as markers of spoilage and putrefaction in food and feed, especially in improperly handled animal products. Detoxification of BAs occurs mainly in the intestinal tract by amine oxidases, but some factors may facilitate intestinal absorption. When consumed in high concentrations, BAs can impair colonic epithelium, intestinal functionality, and may cause other toxicological effects. This study aimed to evaluate the effects of diets based on hydrolyzed protein (hydrolyzed chicken liver powder—HCLP) or conventional intact protein (poultry by-product meal—PBPM) with increasing protein concentrations (24, 32, and 40%) on the consumption and metabolism of biogenic amines in adult dogs. The results showed that PBPM had higher concentrations of putrefactive BAs, as well as the diets with its inclusion. As a result, dogs consumed higher concentrations of putrefactive BAs with diets containing PBPM and higher protein concentrations. Despite the difference in BAs concentrations in the protein sources, there was only an increase in the fecal excretion of phenylethylamine in the HCLP32 and HCLP40 diets and the enzymatic activity of monoamine oxidase in the HCLP24 and PBPM32 diets. Our findings indicate that the inclusion of HCLP reduces the consumption of putrefactive BAs and that the BAs detoxification system is highly efficient in the intestinal tract of dogs. Biogenic amines are synthesized through the bacterial decarboxylation of amino acids, commonly found in high levels in animal by-product meals due to spoilage. Furthermore, biogenic amines and other metabolites can be produced by the fermentation of proteins in the hindgut according to the protein source and concentration of crude protein (CP) in the diet. Thus, this study aimed to evaluate two protein sources (poultry by-product meal (PBPM) and hydrolyzed chicken liver powder (HCLP)) and three CP concentrations (24, 32, and 40%) and their effects on the consumption and fecal excretion of biogenic amines, plasma monoamine oxidase (MAO) and diamine oxidase (DAO) activities, and total antioxidant capacity (TAC) of healthy adult dogs after 30 days of feeding the experimental diets. Twelve dogs were randomly distributed into six treatments (n = 6/treatment): PBPM24 (PBPM with 24% CP); PBPM32 (PBPM with 32% CP); PBPM40 (PBPM with 40% CP); HCLP24 (HCLP with 24% CP); HCLP32 (HCLP with 32% CP); HCLP40 (HCLP with 40% CP). The PBPM and PBPM-based diets had higher concentrations of putrescine, cadaverine, tyramine, histamine, agmatine, and total biogenic amines. In contrast, HCLP and HCLP-based diets contained higher concentrations of spermidine, phenylethylamine, and spermine. The PBPM and PBPM-diets had higher biogenic amine index (BAI) indicating lower quality due to the high content of putrescine, cadaverine and tyramine. Dogs fed diets with PBPM and higher protein concentrations consumed more putrescine, cadaverine, tyramine, agmatine, and total amines (p < 0.0001), while dogs fed with HCLP consumed more spermidine, phenylethylamine, and spermine (p < 0.0001). Fecal excretion of phenylethylamine was greater in dogs fed HCLP32 and HCLP40 diets (p = 0.045). Dogs fed with HCLP tended to excrete more spermidine and tryptamine via feces, while higher protein concentrations tended to increase fecal excretion of cadaverine (p < 0.10). Plasma MAO activity was higher in dogs fed HCLP24 and PBPM32 diets (p = 0.024). The plasma activities of DAO and TAC were not different between diets (p > 0.05). Although we did not evaluate the intestinal activities of MAO and DAO, our results suggest that healthy adult dogs have an efficient deamination process on the gut epithelium. [ABSTRACT FROM AUTHOR]

Fish meal (FM) is an essential product as a primary protein source in the fish feed industry. Due to the expensive price of FM and the negative impact of its high consumption on the environment, alternative protein sources for FM were necessary to be tested. Poultry by-Product meal (PBPM) is a high quality and low-cost protein source. In this study, FM was partially and completely replaced by PBPM in Nile tilapia fingerlings (Oreochromis niloticus) diet to study its effect on biomass performance and nutrient utilization. Six formulas were prepared to replace FM protein with PBPM protein: Maram feed as a commercial control (CC), feed, the experimental control (EC) 0% PBPM, (C3) 32% PBPM, (C4) 67% PBPM, (C5) 100% PBPM-Saudi Radwa Feed company (SRFC), and (C6) 100% PBPM-Con. The study period was extended for 56 days in outdoor ponds. Nile tilapia fingerlings were fed three times daily (initial average weight = 41 g). Final survival ranged between 97% and 72% in all diet treatments and final gain was (41.32g – 14.73g). However, the gain of C4 (41.32) was higher than in the controls CC (38.24) and EC (40.69) also, feed conversion ratios FCR (1.21– 4.29). The best results of growth performance and nutrient utilization were for C4 (67% PBPM). The results of this study showed that poultry by-product meal is a great alternative protein source up to 67% of the fish meal for fish meal for the feeding of Nile tilapia fingerlings. [ABSTRACT FROM AUTHOR]

In order to further close nutrient cycles of aquaponic systems, it could be possible to integrate a third trophic level in the form of insect larvae production (i.e., black soldier fly larvae) to recycle internal waste streams into valuable nutrients. This would present opportunities to formulate sustainable circular aquafeeds that combine these internally available nutrients with complementary external raw materials. The ingredient composition of feeds for such circular multitrophic food production systems (CMFS) may affect fish performance as well as excretion of important dissolved plant nutrients such as N, P and K. Hence, fish meal from catfish processing (CM) as base ingredient was combined with variable levels of poultry by-product meal (PM) and black soldier fly larvae meal (BSFM) into three marine-ingredient-free experimental diets corresponding to hypothetical production scenarios of a CMFS that aims to integrate aquaponics with insect larvae production. These experimental diets and a commercial diet (COM) were compared using isonitrogenous and isolipidic formulations. They were fed to African catfish (Clarias gariepinus) in recirculating aquaculture systems (RAS) and evaluated concerning growth performance and nutrient excretion. All diets resulted in similar total inorganic nitrogen (TIN) excretion, whereas the increase of dietary PM inclusion from 0% (BSF diet) to 20% (MIX diet) and to 41% (PM diet) and concomitant reduction of BSFM inclusion led to increasingly higher soluble reactive phosphorus (SRP) excretion per unit of feed compared to the COM diet. While the PM diet enabled the best growth and feed conversion performance, the MIX and especially the BSF diet produced more similar performance to the COM diet, which generated the highest dissolved K excretion. The MIX and the PM diet resulted in the highest Ca and P, yet lower N content in the fish feces. Results indicate that combining CM with elevated levels of PM in the diet of African catfish could improve growth performance and reduce the need for P fertilization in aquaponics when compared to industrial diets optimized for low environmental impact. Findings are discussed regarding their implications for CMFS and aquaponic feed formulation. [ABSTRACT FROM AUTHOR]

Simple Summary: Fish meal is widely used in aquaculture feed due to its high protein content, balanced amino acid composition, and low anti-nutritional factors. However, with the development of intensive aquaculture, fish meal resources are in short supply and prices are rising. In order to ensure the sustainable development of aquaculture, it is very important to find a low-cost, high-quality protein source to replace fish meal. In this study, substituting fish meal of Chinese soft-shelled turtle (Pelodiscus sinensis) diets with poultry by-product meal was carried out. The results showed that replacing fish meal with 15% poultry by-product meal had no adverse effect on the growth of Chinese soft-shelled turtle (Pelodiscus sinensis), and the 10% poultry by-product meal was beneficial to the growth performance, immunity, and digestive ability. Therefore, it is feasible to use poultry by-product meal as a protein source to replace fish meal in Chinese soft-shelled turtle (Pelodiscus sinensis) feed. To investigate the effect of poultry by-product meal (PBM) replacing fish meal on the growth and intestinal health of Chinese soft-shelled turtle (Pelodiscus sinensis). Four experimental diets were prepared. Fish meal was replaced by 0 (control group, PBM0), 5% (PBM5), 10% (PBM10), and 15% (PBM15) PBM. Compared to the control group, final body weight, weight gain, and specific growth rate were significantly increased, while feed conversion rate decreased significantly in the PBM10 group (p < 0.05). The PBM15 group significantly increased the moisture content and significantly decreased the ash content of the turtles (p < 0.05). The PBM5 and PBM15 groups significantly decreased the whole-body crude lipid (p < 0.05). The serum glucose content increased significantly in the PBM10 group (p < 0.05). The liver malonaldehyde content significantly decreased in the PBM5 group and in the PBM10 group (p < 0.05). Liver glutamic-oxalacetic transaminase and intestinal pepsin activity were increased significantly in the PBM15 group (p < 0.05). The expression of the intestinal interleukin 10 (IL-10) gene was significantly down-regulated in the PBM10 group and the PBM15 group (p < 0.05), the expression of the intestinal interferon-γ (IFN-γ), interleukin-8 (IL-8), and liver toll-like receptor 4 (TLR4) and toll-like receptor 5 (TLR5) genes were significantly up-regulated in the PBM5 group (p < 0.05). In summary, poultry by-product meal can be used as a protein source to replace fish meal in turtle feed. Based on quadratic regression analysis, the optimal replacement ratio is 7.39%. [ABSTRACT FROM AUTHOR]

An 8 weeks feeding trail was conducted to evaluate the potential of poultry by-product meal (PBM) replacing fish meal (FM) in the diet of juvenile large yellow croaker (Larimichthys crocea). Five iso-nitrogenous (45% crude protein), iso-lipidic (10% crude lipid) and iso-energetic (about kcal 400 g diet −1) diets were formulated with 0, 25%, 50% 75% and 100% FM being replaced by PBM (marked as FM, PBM25, PBM50, PBM75 and PBM100). Crystal methionine and lysine were added into PBM-containing diets to match its concentration in FM diet. Each diet was randomly assigned to triplicate groups of 30 fish (initial weight 18.43 ± 1.28 g) in floating sea cages. The weight gain, specific growth rate and feed efficiency of L. crocea decreased significantly when the replacement level of FM was higher than 25%. The feed intake of fish fed PBM100 was significantly lower than those fed FM, PBM25 and PBM50. Juveniles fed PBM-containing diets showed significantly lower value of muscular thickness in intestine when compared to those fed FM. Villi length decreased significantly when the replacement of FM in diets was more than 50%. Fish fed FM diet had the relative higher abundances of Exiguobacterium (from order to genus), Bacillus (from order to genus), Pseudomonadales (from order to genus) and Acinetobacter genus, those fed PBM25, PBM50 and/or PBM75 showed higher abundance of Peptostreptococcaceae and Vibrio. Overall, PBM replacing dietary FM may inhibit growth performance of L. crocea through reducing digestibility via declining the abundance of intestinal bacteria that producing digestive enzyme, and improving the abundance of pathogen. Peptostreptococcaceae and Vibrio could be the indicator in the intestinal of L. crocea fed high PBM diets. The optimum dietary FM replacement level by PBM was 25% for L. crocea.

The liver health of Gilthead sea bream and European sea bass, fed with fish meal-free diets, including various proportions of plant proteins, as well as insect and poultry by-product meals, was investigated through biochemical and histological analyses using a new liver index (LI) formula. Four isoproteic (45% Dry Matter, DM) and isolipidic (20% DM) diets were compared, including a plant-based control diet (CV) and three other test diets, in which 40% of a plant protein-rich ingredient mixture was replaced with meals from Hermetia illucens (H40) or poultry by-product (P40) alone, or in combination (H10P30). The trials lasted 12 and 18 weeks for sea bream and sea bass, respectively. The results obtained thus far highlighted species-specific differences in the physiological response to dietary changes. In sea bream, the biochemical and histological responses suggest favorable physiological and liver health statuses, with higher serum cholesterol (CHO) and triglyceride (TAG) levels, as well as moderate hepatocyte lipid accumulation, with the H10P30 diet compared to the CV (p < 0.05). In sea bass, all diets resulted in elevated serum TAG levels and lipid accumulation in the liver, particularly in fish fed the P40 one (p < 0.05), which resulted in the highest LI, coupled with a higher frequency of severe lipid accumulation, hypertrophy, cord loss, peripheral nuclei displacement, and pyknosis. In conclusion, sea bream adapted well to the test diets, whereas sea bass exhibited altered hepatic lipid metabolism leading to incipient liver steatosis, likely due to the high lipid contents of the diets, including the insect and poultry meals. The LI formula developed in this study proved to be a reliable tool for assessing the effects of dietary changes on the liver health of sea bream and sea bass, consistent with biochemical and histological findings.

ABSTRACT Protein quality is related to amino acid composition and digestibility. Accurate evaluation of apparent digestibility coefficients (ADCs) of nutrients in commonly used feedstuffs is paramount for formulating efficient aquafeed. ADCs of soybean meal (SBM) and poultry by-product meal (PBM) were evaluated using reference diets formulated with two types of ingredients (semi-purified [SP] and practical [P]) for juvenile Nile tilapia ( Oreochromis niloticus, Linnaeus) of the GIFT strain. Groups of 20 juveniles (65.05 ± 12.37 g) were fed twice a day to apparent satiety with one of the four experimental diets (SBM-SP, SBM-P, PBM-SP, and PBM-P) in quadruplicate for 30 days. After the last feeding, feces were collected by siphoning hourly and the ADCs of dry matter, protein, and amino acids (AAs) were calculated. Nile tilapia exhibited a high capacity to digest SBM and PBM, with most ADCs exceeding 90 %. The type of reference diet affected the ADCs of protein and AAs on the test ingredients, with the SP reference diet providing the highest ADC, mainly in SBM. Digestibility data generated with a P-type reference diet demonstrated more practical relevance than those generated with an SP-type reference diet. They can be applied in digestibility studies for Nile tilapia.

Florida pompanos (15.3 g initial average weight) were fed one of seven open‐source experimental diets to examine the effects of the complete removal of fishmeal (FM) and fish oil (FO) upon growth over a 12‐week period. Diets were compared against an investigational feed containing FM and FO. Three different oils, derived from flax, canola and an alga, alone or in combination, were evaluated as alternatives for FO. FM was replaced in the experimental diets using a blend of proteins that included poultry by‐product meal, hydrolysed soy and soy and corn protein concentrates. The study was undertaken in a recirculating aquaculture system and under hyposaline (3 g/L) conditions with each diet being examined in triplicate. At trial end, fish fed some diets increased their initial body weight by over 300%, and there were no differences (p > 0.05) between diets for feed efficiency, condition or K‐factor, whole‐body composition, intraperitoneal fat (%), hepatosomatic index or fillet yield (%). All experimental diets achieved parity with the FM/FO control feed. Differences were detected in fillet fatty acids among diets, with the latter corresponding to dietary profiles. This study represents the first with pompano to evaluate diets simultaneously void of FM and FO and provides strong evidence to support the practicability of removing FM/FO from pompano diets. [ABSTRACT FROM AUTHOR]

The present study was conducted to investigate the dietary replacement of fish meal with poultry by-product meal (PBM) on the growth performance, immunity, antioxidant properties, and intestinal health of red swamp crayfish (Procambarus clarkia). A diet containing 20% fish meal (FM) and complex plant ingredients as the main protein resources was set as the FM group (crude protein 32%, crude lipid 6%). Four diets replacing 25%, 50%, 75%, and 100% fish meal of the FM diet with PBM were set as the PBM25, PBM50, PBM75, and PBM100 groups, respectively. Compared to the FM group, the PBM100 diet significantly decreased growth performance and feed utilization of crayfish, while markedly increasing the activity of serum aspartate aminotransferase. The immune response was depressed in crayfish fed the PBM100 diet as the activities of serum lysozyme and phenoloxidase, gene expression of anti-lipopolysaccharide factors (alf), cyclophilin A (cypa), crustin , and hemocyanin-1 (hep - 1) in hepatopancreas were remarkably decreased. The activities of antioxidases and expression of antioxidant-relevant genes in the hepatopancreas were not influenced by PBM inclusion. Crayfish fed different diets exhibited no obvious symptoms of enteritis, but the PBM100 diet destructed intestinal morphology by significantly decreasing the average length of longitudinal ridges. The α-diversity and overall community structure were not significantly influenced but variations were found in the relative abundance of some genera by PBM inclusion. In summary, CAP could successfully replace 75% dietary FM in a basal diet containing 20% fish meal, while higher CAP level compromised growth performance, immunity, and intestinal histology of crayfish. • PBM replacing 75% FM did not reduce growth performance and intestinal morphology of crayfish. • PBM replacing 75% FM did not depress immunity and hepatopancreas health of crayfish. • PBM inclusion showed no adverse effects on antioxidant properties of crayfish. • Overall intestinal microbial community structure was not altered by PBM inclusion. • PBM changed abundances of some intestinal bacteria genus of crayfish. [ABSTRACT FROM AUTHOR]

Animal protein feedstuffs, including poultry by‐product meal (PBM), spray‐dried porcine solubles (SPS), hydrolysed feather meal (HFM) and spray‐dried egg product (SEP), were used to replace 5% fish meal (FM) in the diet of Macrobrachium nipponense, respectively, to evaluate their effects on growth performance. A diet containing 25% FM was used as the control treatment. The various diets were fed to quadruplicate groups of prawns for 10 weeks. Results showed that there were no significant differences in survival, final body weight or weight gain among different treatments. The feed conversion ratio of the SPS group was significantly higher than that of the control group. The protein efficiency ratio was significantly higher in the SEP group than in the other groups. The feed intake of the SEP group was significantly lower than that of the control group. Animal protein feedstuffs significantly affected the composition of prawns' muscle, while slightly affecting the muscle amino acid profile. Moreover, animal protein feedstuffs significantly affected the haemolymph biochemical parameters and hepatopancreas lipase and α‐amylase activities. These four animal protein feedstuffs regulated the target of rapamycin (TOR) and activated transcription factor 4 (ATF4) expressions in the hepatopancreas and muscle. Meanwhile activating transcription factor 3 (ATF3) in muscle was significantly up‐regulated. Moreover, acetyl‐CoA carboxylase (ACC) and fatty acid synthase (FAS) in hepatopancreas were significantly down‐regulated in all treatments, while FAS was only down‐regulated in the HFM group. In general, animal protein feedstuffs in the present study are all good candidates to partially replace FM in the diet of M. nipponense. Moreover, SEP is the best one among these animal protein feedstuffs. [ABSTRACT FROM AUTHOR]

The present study evaluated the effects of partially substituting fish meal (FM) with poultry by-product meal (PBPM) on the growth, muscle composition, and tissue biochemical parameters of coho salmon (Oncorhynchus kisutch) post-smolts. Five isonitrogenous (7.45% nitrogen) and isoenergetic (18.61 MJ/kg gross energy) experimental diets were made by substituting 0%, 10%, 20%, 40%, and 60% FM protein with PBPM protein, which were designated accordingly as PBPM0 (the control), PBPM10, PBPM20, PBPM40, and PBPM60, respectively. Each diet was fed to triplicates of ten post-smolts (initial individual body weight, 180.13 ± 1.32 g) in three floating cages three times daily (6:50, 11:50, and 16:50) to apparent satiation for 84 days. Both specific growth rate (SGR) and protein efficiency ratio did not differ significantly (p > 0.05) among the control, PBPM10, and PBPM20 groups, which were remarkably (p < 0.05) higher than those of the PBPM40 and PBPM60 groups. Feed conversion ratio varied inversely with SGR. The PBPM replacement had no remarkable effects on the morphological indices and proximal muscle components. The control and PBPM10 groups led to significantly higher muscle contents of leucine, lysine, and methionine than groups of higher PBPM inclusion. The groups of PBPM40 and PBPM60 obtained significantly (p < 0.05) higher serum alanine aminotransferase and aspartate aminotransferase activities than the control and low PBPM inclusion groups. The control group had significantly higher albumin and total cholesterol contents than the groups with PBPM inclusion. The control group had significantly higher triglycerides content than the PBPM60 group. The PBPM60 group had significantly lower contents of high-density lipoprotein, low-density lipoprotein, and total protein than the control and PBPM10 groups. The high PBPM replacement level up to 40% and 60% had adverse effects on hepatic malondialdehyde levels. The catalase and superoxide dismutase activities were not affected by low PBPM inclusion, but significantly decreased in high-PBPM-inclusion groups. Based on broken-line regression analysis of SGR and PER, the optimum dietary PBPM replacing level was evaluated to be 16.63–17.50% of FM protein for coho salmon post-smolts.

Biogenic amines are synthesized through the bacterial decarboxylation of amino acids, commonly found in high levels in animal by-product meals due to spoilage. Furthermore, biogenic amines and other metabolites can be produced by the fermentation of proteins in the hindgut according to the protein source and concentration of crude protein (CP) in the diet. Thus, this study aimed to evaluate two protein sources (poultry by-product meal (PBPM) and hydrolyzed chicken liver powder (HCLP)) and three CP concentrations (24, 32, and 40%) and their effects on the consumption and fecal excretion of biogenic amines, plasma monoamine oxidase (MAO) and diamine oxidase (DAO) activities, and total antioxidant capacity (TAC) of healthy adult dogs after 30 days of feeding the experimental diets. Twelve dogs were randomly distributed into six treatments (n = 6/treatment): PBPM24 (PBPM with 24% CP); PBPM32 (PBPM with 32% CP); PBPM40 (PBPM with 40% CP); HCLP24 (HCLP with 24% CP); HCLP32 (HCLP with 32% CP); HCLP40 (HCLP with 40% CP). The PBPM and PBPM-based diets had higher concentrations of putrescine, cadaverine, tyramine, histamine, agmatine, and total biogenic amines. In contrast, HCLP and HCLP-based diets contained higher concentrations of spermidine, phenylethylamine, and spermine. The PBPM and PBPM-diets had higher biogenic amine index (BAI) indicating lower quality due to the high content of putrescine, cadaverine and tyramine. Dogs fed diets with PBPM and higher protein concentrations consumed more putrescine, cadaverine, tyramine, agmatine, and total amines (p < 0.0001), while dogs fed with HCLP consumed more spermidine, phenylethylamine, and spermine (p < 0.0001). Fecal excretion of phenylethylamine was greater in dogs fed HCLP32 and HCLP40 diets (p = 0.045). Dogs fed with HCLP tended to excrete more spermidine and tryptamine via feces, while higher protein concentrations tended to increase fecal excretion of cadaverine (p < 0.10). Plasma MAO activity was higher in dogs fed HCLP24 and PBPM32 diets (p = 0.024). The plasma activities of DAO and TAC were not different between diets (p > 0.05). Although we did not evaluate the intestinal activities of MAO and DAO, our results suggest that healthy adult dogs have an efficient deamination process on the gut epithelium.

To reveal direct effects of various protein sources on digestive physiology of red seabream, Pagrus major (38.5 ± 0.4 g), six different protein sources of fishmeal (FM), soybean meal (SBM), corn gluten meal (CGM), soy protein concentrate (SPC), poultry by-product meal (PBM), and poultry-feather meal (PFM) were orally administered to fish (2 mg protein/g body weight) and sampled at 1.5 h and 3 h after administration. Gallbladder weight of fish administered FM, PBM, and PFM decreased after administration (p < 0.0001), while no difference was observed in the other ingredients compared to a non-protein sham control group, indicating that animal protein sources could more strongly stimulate bile secretion than plant protein sources in red seabream. Trypsin and chymotrypsin activity in the intestinal content markedly increased by the FM, SBM, and PFM administration (p < 0.0001). Lipase and amylase activity was also increased by FM and SBM but also by CGM for lipase and by PBM and PFM for amylase (p < 0.0001). These indicate that stimulation effect of the secretion of digestive enzymes is largely different among the protein sources. This might be due to the absorptive capacity of the protein source since intestinal absorption parameter genes (anpep, cpa, ggt1, and atp1a2) also increased by the FM, SBM, PBM or PFM (p < 0.05). In addition to the secretion levels of bile and digestive enzymes, gene expression levels of bile related genes (cyp7a1, cyp8b1, and shp) and digestion-regulating genes (casr and cck) were increased by the FM, SBM, PFM, and/or PBM administration, suggesting that animal proteins and SBM could be potent digestive stimulants compared to CGM and SPC. This study first revealed that single protein sources directly influence digestive enzyme secretion and bile secretion in fish. Information about the direct effect of each single source on digestive physiology could help to design feed formulation with less fishmeal. [ABSTRACT FROM AUTHOR]

Simple Summary: Processed animal proteins, such as poultry by-product meal (PBM) and insect meal from black soldier fly (BSFM), are receiving growing interest as alternative or complementary protein sources for carnivorous farmed fish diets, due to their high nutritional value and low environmental footprint. The present study aimed to evaluate the effects of PBM and BSFM as partial substitutes for vegetable protein in fishmeal-free diets on growth, whole-body composition, nutrient-energy mass balance and retention, digestive functions, stress, metabolic status, innate immunity, and liver health in rainbow trout (Oncorhynchus mykiss). The overall results showed that fishmeal-free diets, including high levels of both PBM and BSFM, either singly or in combination, improved growth, dietary nutrient and energy utilization, and gut function relative to a plant-protein control diet or a fishmeal-based one, with no detrimental effects on fish welfare. This study compared the nutrient-energy retention, digestive function, growth performance, and welfare of rainbow trout (ibw 54 g) fed isoproteic (42%), isolipidic (24%), fishmeal-free diets (CV) over 13 weeks. The diets consisted of plant-protein replacement with graded levels (10, 30, 60%) of protein from poultry by-product (PBM) and black soldier fly H. illucens pupae (BSFM) meals, either singly or in combination. A fishmeal-based diet was also tested (CF). Nitrogen retention improved with moderate or high levels of dietary PBM and BSFM relative to CV (p < 0.05). Gut brush border enzyme activity was poorly affected by the diets. Gastric chitinase was up-regulated after high BSFM feeding (p < 0.05). The gut peptide and amino acid transport genes were differently regulated by protein source and level. Serum cortisol was unaffected, and the changes in metabolites stayed within the physiological range. High PBM and high BSFM lowered the leukocyte respiratory burst activity and increased the lysozyme activity compared to CV (p < 0.05). The BSFM and PBM both significantly changed the relative percentage of lymphocytes and monocytes (p < 0.05). In conclusion, moderate to high PBM and BSFM inclusions in fishmeal-free diets, either singly or in combination, improved gut function and nutrient retention, resulting in better growth performance and the good welfare of the rainbow trout. [ABSTRACT FROM AUTHOR]

Proteases are the enzymes responsible for the hydrolysis of complex proteins into simpler units for better digestion and absorption of nutrients. This study was conducted to determine the optimum supplementation level and effects of dietary protease addition in poultry by‐product meal‐based diet (PBM) on growth performance, nutrient digestibility, digestive enzyme activities and physiochemical parameters of juvenile rohu, Labeo rohita (initial weight: 11.33 ± 0.02 g). For this purpose, seven iso‐nitrogenous and iso‐lipidic experimental diets were formulated to contain a positive control (PC) diet (containing fishmeal and no protease), a negative control (NC) diet (containing PBM and no protease) and five other PBM‐based diets supplemented with exogenous protease at the levels of 150, 300, 450, 600 and 750 mg/kg diet. Results indicated that growth performance and body indices of fish fed protease supplemented diets were higher (p < 0.05) compared with those fed the NC diet, while maximum increase was recorded at 450 mg/kg protease supplementation level, which was similar to the PC diet (p > 0.05). Protease supplementation up to 450 mg/kg level linearly improved (p < 0.05) the whole‐body proximate composition and digestibility of dry matter (DM), crude protein (CP), crude lipid (CL) and crude ash (CA) in rohu juveniles. A similar trend (p < 0.05) was observed in the activities of amylases, lipases and proteases in intestinal and hepatopancreatic tissues, peaking at 450 mg/kg which was also similar (p > 0.05) to the PC diet. Protease supplementation significantly improved (p < 0.05) haemoglobin (Hb), haematocrit (Htc) and red blood cells (RBCs) of juveniles while, white blood cells (WBCs) and serum indices remained unaffected (p > 0.05). Based on quadratic regression analysis, the optimal dietary protease supplementation in PBM‐based diet for rohu was 433 mg/kg. Conclusively, increase in protease supplementation from 0 to 450 mg/kg levels improved the fish performance and decreased thereafter with further increase in protease levels (600–750 mg/kg). [ABSTRACT FROM AUTHOR]

The relative shortage of fishmeal is challenging the sustainable development of aquaculture industry. A 56‐day feeding trial was conducted to evaluate the efficacy of fishmeal replacement by poultry by‐product meal (PBM) in juvenile obscure pufferfish. The basal diet with 45% (dry matter) fishmeal was used as the control diet, and in the four experimental diets PBM was added into the control diet to replace fishmeal at the level of 15% (PBM15), 30% (PBM30), 45% (PBM45) and 60% (PBM60) respectively. Each diet was fed to triplicate tanks, each of which was stocked with 30 fish. PBM30 did not significantly affect the growth performance, nutrient apparent digestibility coefficient, proximate composition, amino acid profile, muscle texture and serum biochemical indices (p > 0.05). PBM45 did not significantly (p > 0.05) affects the weight gain, but reduced the feed efficiency ratio (p < 0.05). PBM60 resulted in significantly reduced fish growth (p < 0.05). PBM‐supplemented diets resulted in lower contents of long chain‐polyunsaturated fatty acid in the liver, but higher deposition of C18:1n‐9 and C18:2n‐6 in experimental fish (p < 0.05). In conclusion, replacing 30% fishmeal with PBM in the diet did not compromise the growth performance, feed utilisation, health status and muscle texture of farmed obscure pufferfish. [ABSTRACT FROM AUTHOR]

The way to grow cheaper fish is to use protein sources that can be an alternative to fish meal that is considered on the most expensive feed ingredient in fish feeds. For this purpose, poultry by-product meal (PBM) which is locally sourced and cheaper than fish meal, was used to replace 25, 50, 75 and 100 % of fish meal protein in rainbow trout (Oncorhynchus mykiss) poultry by-product meal was not included in the control feed. Feeds in this investigation were prepared as similar protein (43% CP) and digestible energy (13.28 MJ. DE kg-1) levels. A total of 300 rainbow trout with 50.6±1.35 g of average initial weight were used in the investigation. All the diets including the control were fed the rainbow trout in triplicate for 70 days. At the end of the trial, the difference between feeds I, II, II, IV and feed V was significant in terms of average live weight gain (ALWG) and feed consumption throughout the investigation (P<0.05). No difference was observed in terms of feed conversion ratio (FCR) and protein conversion ratio (PER). However, considering the cost of producing 1 kg of fish, it is obvious that although the cheapest fish is obtained from the group fed with IV and V feeds (P<0.05), it will take weeks for the fish in these groups to reach the average live weight of groups I, II and III. As a result, it was concluded that poultry by-product meal could be used instead of 75% of fish meal protein in trout feeds in terms of a normal fish development process. [ABSTRACT FROM AUTHOR]

A 7‐week growth trial was conducted to assess the potential of using soybean protein isolate (SPI) to replace poultry by‐product meal (PBM) protein in low fishmeal (FM) diets for juvenile hybrid grouper (Epinephelus fuscoguttatus ♀ × Epinephelus lanceolatus ♂). Seven isoproteic (490 g kg−1) and isolipidic (90 g kg−1) experimental diets were formulated, including six low FM diets and a high FM diet (HFMP). The low FM diets contained 0, 74.8, 149.7, 224.5, 299.4 and 374.2 g kg−1 SPI, replacing approximately 0%, 20%, 40%, 60%, 80% and 100% of the PBM protein (designated as SPIP0, SPIP20, SPIP40, SPIP60, SPIP80 and SPIP100, respectively). Each diet was hand‐fed to triplicate groups of 12 hybrid grouper juveniles (average initial body weight: 14.30 ± 0.1 g per fish). After being fed for 7 weeks, fish fed with HFMP and SPIP60 showed significantly higher (p <.01) weight gain percentage (WG%), protein efficiency ratio and protein productive value than fish fed with other experimental diets. These three parameters were elevated with the increment in PBM protein (PBMP) replacements, reaching the peak value at the 60% replacing level, and then, they were significantly reduced at the 80% or 100% replacing level. Analysis of the two‐slope straight broken‐line model showed that the maximum PBMP replacement level by SPI protein (SPIP) at the intercept value of WG% was estimated to be 60%. Feed conversion ratio showed an opposite tendency of variation to WG%. Fish fed with SPIP80 and SPIP100 displayed lower mRNA levels of hepatic insulin‐like growth factor‐1, hypothalamus neuropeptide Y and head‐kidney nuclear factor erythroid 2‐related factor 2 than fish fed with other experimental diets. Generally, 60% of PBM protein could be replaced with SPI protein in low FM diets for hybrid grouper. [ABSTRACT FROM AUTHOR]

To investigate the effect of poultry by-product meal (PBM) replacing fish meal on the growth and intestinal health of Chinese soft-shelled turtle (Pelodiscus sinensis). Four experimental diets were prepared. Fish meal was replaced by 0 (control group, PBM0), 5% (PBM5), 10% (PBM10), and 15% (PBM15) PBM. Compared to the control group, final body weight, weight gain, and specific growth rate were significantly increased, while feed conversion rate decreased significantly in the PBM10 group (p < 0.05). The PBM15 group significantly increased the moisture content and significantly decreased the ash content of the turtles (p < 0.05). The PBM5 and PBM15 groups significantly decreased the whole-body crude lipid (p < 0.05). The serum glucose content increased significantly in the PBM10 group (p < 0.05). The liver malonaldehyde content significantly decreased in the PBM5 group and in the PBM10 group (p < 0.05). Liver glutamic-oxalacetic transaminase and intestinal pepsin activity were increased significantly in the PBM15 group (p < 0.05). The expression of the intestinal interleukin 10 (IL-10) gene was significantly down-regulated in the PBM10 group and the PBM15 group (p < 0.05), the expression of the intestinal interferon-γ (IFN-γ), interleukin-8 (IL-8), and liver toll-like receptor 4 (TLR4) and toll-like receptor 5 (TLR5) genes were significantly up-regulated in the PBM5 group (p < 0.05). In summary, poultry by-product meal can be used as a protein source to replace fish meal in turtle feed. Based on quadratic regression analysis, the optimal replacement ratio is 7.39%.

SUMMARY: Farmers and researchers in developing countries are evaluating the use of fish meal in broiler diets due to high cost and product variability. This study evaluated the effects of replacing fish meal with either soybean meal or poultry by-product meal on broiler performance and total feed cost per kilogram of gain. Three dietary treatments were manufactured to contain soybean meal and fish meal, soybean meal or soybean meal, and poultry by-products meal. Diets were balanced for lysine and fed in mash form. A total of 900 1-day-old male Cobb 500 broilers were randomly assigned to pens with 25 chicks per pen and reared for 42 d. Overall, 42 d broilers fed fish meal diets had lower body weights (P ≤ 0.05) compared to those fed soybean meal and poultry by-products meal diets but adjusted feed conversion ratio was similar (P ≥ 0.05) for all treatments. Replacing fish meal with either soybean meal or poultry by-products meal resulted in higher body weights and average daily feed intake but similar adjusted feed conversion ratio for all birds and lower feed cost per kilogram of gain.

A 60‐day feeding trial was conducted to examine the effects of replacing fish meal protein with poultry by‐product meal (PBM) and bioprocessed poultry by‐product meal (BPBM) on growth performance, nutrient utilization, whole‐body chemical and amino acid composition and haemato‐biochemical responses in GIFT tilapia reared in floating cages. Seven isonitrogenous (320 g/kg crude protein), isolipidic (50 g/kg crude lipid) and isoenergetic (17 MJ/kg) experimental diets were formulated by replacing 0%, 33.33%, 66.67% and 100% of fish meal protein with PBM and BPBM respectively and referred as Control, PBM 33.33, PBM 66.67, PBM 100, BPBM 33.33, BPBM 66.67 and BPBM 100. Triplicate groups of 30 GIFT tilapia juveniles with an average initial weight of 11.28 ± 0.14 g were fed with experimental diets daily thrice until apparent satiation (08:00, 12:00 and 16:00 h). Among PBM and BPBM dietary groups, significantly (p < 0.05) higher growth performance and nutrient utilization were observed in fish fed BPBM 66.67 group compared to other treatment diets including control diet. No significant difference (p > 0.05) was observed in survival rate of GIFT tilapia fed different levels of PBM and BPBM‐incorporated diets. Moreover, dietary inclusion of PBM and BPBM did not (p > 0.05) affect the whole‐body chemical and amino acid composition and haemato‐biochemical responses in GIFT tilapia. It is concluded that PBM and BPBM can completely replace dietary fish meal protein in GIFT tilapia diets without any negative impact on growth performances, nutrient utilization and blood haemato‐biochemical responses. However, significantly higher growth performances and nutrient utilization were obtained in fish fed BPBM 66.67 diet. [ABSTRACT FROM AUTHOR]

Hybrid sturgeon (Acipenser schrenckii♀×Acipenser baerii♂) were fed with four isonitrogenous (approximately 43.0%) and isolipidic (approximately 13.6%) diets: FM‐based diet (lysine control diet, LC diet), poultry by‐product meal totally substitute diet (lysine low diet, LL diet), LL diet supplemented lysine to match the LC diet group level (lysine medium diet, LM diet) and LL diet supplemented lysine over the LC diet group level (lysine high diet, LH diet) for 8 weeks to determinate the effect of dietary lysine supplementation on growth performance, metabolism and immunity response. The results indicated that compared with control diet, LL diet led to depressed growth performance and feed utilization. Lysine supplementation had a significant effect on improving the growth performance and feed utilization. Moreover, LL diet also decreased the plasma‐free amino acid concentration, nutrient content and mRNA expression level of IGF system and increased plasma immunity indexes and gene expression level of HSP70 than the control diet. LM diet had marked efficiency to eliminate the differential effects caused by lysine insufficiency. However, high‐level lysine addition had undesirable effect on regulating the growth performance, feed utilization, plasma‐free amino acid concentration, nutrient content, immunity indexes and gene expression level. Present study demonstrated that poultry by‐product meal with lysine addition could totally substitute FM without adverse effects on growth performance, plasma AA concentration, nutrient content and immune response in hybrid sturgeon. Our results provide a solid evidence for using lysine to improve the body growth performance and metabolism in hybrid sturgeon. [ABSTRACT FROM AUTHOR]

The effects of fish meal (FM) protein replaced with a mixture of poultry by‐product meal (PBM) and fermented soybean meal (FSBM) on the growth performance of Asian seabass (Lates calcarifer) was investigated. Seven diets were formulated to replace 0% (CON−), 0% (CON+), 20% (MPS20), 40% (MPS40), 60% (MPS60), 80% (MPS80) and 100% (MPS100) FM protein with a mixture of 60% PBM and 40% FSBM. Treatment diets except CON− contained feed attractants; each diet was randomly assigned to triplicate groups of ten 1.27 g fish for 6 weeks. The fish fed the CON−, CON+, MPS20, MPS40 and MPS60 diets showed no significant differences in weight gain percentage (WG%) and specific growth rate (SGR), whereas those fed the MPS100 diet had the lowest WG% and SGR. The crude lipid of fish muscle ranged from 66 to 71 g/kg, whereas that of fish liver ranged from 372 to 426 g/kg. The amounts of polyunsaturated fatty acid (PUFA) and n‐3 LC‐PUFA of fish muscle decreased as the FM protein replacement level increased. A mixture of 60% PBM and 40% FSBM would be able to substitute FM protein for up to 60% without adverse effects on the growth performance of Asian seabass. [ABSTRACT FROM AUTHOR]

This study compared the nutrient-energy retention, digestive function, growth performance, and welfare of rainbow trout (ibw 54 g) fed isoproteic (42%), isolipidic (24%), fishmeal-free diets (CV) over 13 weeks. The diets consisted of plant-protein replacement with graded levels (10, 30, 60%) of protein from poultry by-product (PBM) and black soldier fly H. illucens pupae (BSFM) meals, either singly or in combination. A fishmeal-based diet was also tested (CF). Nitrogen retention improved with moderate or high levels of dietary PBM and BSFM relative to CV (p < 0.05). Gut brush border enzyme activity was poorly affected by the diets. Gastric chitinase was up-regulated after high BSFM feeding (p < 0.05). The gut peptide and amino acid transport genes were differently regulated by protein source and level. Serum cortisol was unaffected, and the changes in metabolites stayed within the physiological range. High PBM and high BSFM lowered the leukocyte respiratory burst activity and increased the lysozyme activity compared to CV (p < 0.05). The BSFM and PBM both significantly changed the relative percentage of lymphocytes and monocytes (p < 0.05). In conclusion, moderate to high PBM and BSFM inclusions in fishmeal-free diets, either singly or in combination, improved gut function and nutrient retention, resulting in better growth performance and the good welfare of the rainbow trout.

Two feeding trials were conducted to investigate the utilization of poultry by-product meal (PBM) in the post-larvae and juveniles of giant freshwater prawn, Macrobrachium rosenbergii. In experiment 1, five diets were formulated using PBM to replace fish meal protein at 0-100% replacement level at 25% interval. The growth performance was highest in diet with 75% replacement level. Feed conversion ratio (FCR) ranged from 1.52 to 1.88 and survival was fairly high (79.37–83.73%). In experiment 2, seven diets with higher replacement levels of fish meal protein with PBM protein (starting at 75% replacement level) were fed to triplicate groups of the juvenile prawn. The best growth performance was obtained in diet without fishmeal. Meanwhile, survival rate (83.33–89.56%) did not show any significant difference among the treatments. The result showed that high-quality PBM is a good candidate to replace fish meal protein in the diet and its utilization improved with the size of giant freshwater prawn. [ABSTRACT FROM AUTHOR]

The objectives were to compare the effectiveness of poultry by-product meal (PBM) with xylose-treated soybean meal (x-SBM) as a conventional protein source and rumen-undegraded protein (RUP):rumen-degraded protein (RDP) ratio on nutrient digestibility, nitrogen metabolism, and production of early- to mid-lactation Holsteins. Twelve multiparous cows averaging (mean ± SD) 50 ± 9 days in milk were randomly assigned to a replicated 4 × 4 Latin square design within a 2 × 2 factorial arrangement of treatments. Each period was 28 days in length. Treatments were RUP sources (PBM or x-SBM) with either a high or a low RUP:RDP ratio (high ratio = 40:60 or low ratio = 36:64; based on % of crude protein (CP)). Experimental diets were balanced to be similar in protein and energy contents (CP = 16.7% of DM; NEL = 1.67 Mcal/kg DM). Prior to diet formulation, an in situ pilot experiment was conducted to estimate the RUP fractions of x-SBM and PBM as 63.9% and 54.1% of CP, respectively. Treatments had no effect on ruminal pH and total volatile fatty acid (VFA) and molar percentage of individual VFAs. Treatments had no effect on total tract apparent digestibility of DM, OM, and neutral detergent fiber (NDF), with the exception of N that was greater in diets with a low RUP:RDP ratio (68.2 vs. 70.1% of DM). DM consumption was 0.70 kg/day higher when cows were fed PBM diet compared with x-SBM diet. No treatment effect was observed on milk yield and milk composition; however, milk protein yield and milk urea N were greater in cows fed PBM. Inclusion of PBM in the diet in substitution to x-SBM resulted in increased blood levels of urea N, cholesterol, and non-esterified fatty acid (NEFA). There was no interaction between the RUP source and the RUP:RDP ratio for urinary and fecal N excretion. Efficiency of N utilization expressed as milk N secretion as a proportion of N intake tended to be greater in cows fed PBM. Feeding diets with a low ratio of RUP:RDP increased efficiency of milk production expressed as milk yield as a proportion of total N excretion (fecal and urinary N). Feeding a diet with PBM supported milk production comparable with x-SBM and had positive effects on feed intake, milk protein yield, and milk N efficiency. [ABSTRACT FROM AUTHOR]

Poultry by-product meal (PBM) has the good properties to replace fishmeal. Present study was conducted to assess the capability of PBM in substituting fishmeal in hybrid grouper (Epinephelus fuscoguttatus♀× Epinephelus lanceolatus♂). Six practical diets (52 % crude protein, 12.5 % crude lipid) were formulated with differently PBM replaced level: 0 % (control diet), 20 %, 40 %, 60 %, 80 % and 100 % (namely PBM0, PBM20, PBM40, PBM60, PBM80 and PBM100, respectively). Hybrid grouper with the initial body weight of 80.00 ± 0.02 g were fed different diets at the circulating water system for 8 weeks. Results presented that compared with the control diet (weight gain ratio: 308.83 ± 2.56 %, specific growth performance: 2.52 ± 0.01 %/d), significant differences were not found in the weight gain ratio (286.42 ± 3.65 %) and specific growth performance (2.42 ± 0.02 %/d) after 60 % fishmeal protein replaced by PBM. Higher inclusion of PBM in the diet had markedly decreased growth performance (P < 0.05). Fish fed with PBM40 diet made no significant effect on the feed, protein and lipid efficiency ratio (1.19±0.01, 2.29±0.01, 9.33±0.12) than the fish fed with PBM0 diet (1.24±0.01, 2.40±0.02, 9.80±0.07). However, the PBM60 diet decreased the feed, protein and lipid efficiency ratio (1.12±0.01, 2.15±0.02, 9.08±0.10) significantly than the control diet (P < 0.05). Moreover, dietary 60 % PBM inclusion level also had no significant effect on decreasing the whole body, muscle and plasma proximate nutrient contents and whole body amino acids, fatty acids contents compared to the control diet group. Based on the results, PBM could successfully replace 40 %–60 % protein from fishmeal in the formulated diets for the hybrid grouper. Present study proposed the supreme inclusion level of PBM in the diets which had important significance to aquafeeds industry.

Poultry by‐product meal (PBM) is a popular animal‐based protein source tested in aquaculture feed formulations for replacing fishmeal (FM), mainly due to its high protein content, relatively cheap price and broad availability. However, due to the well‐documented variability in success of PBM inclusions, a meta‐analysis approach was utilized to summarize the efficacy and success of PBM inclusion in aquaculture diet formulations substituting FM. Hedges'g effect sizes were calculated by quantitatively comparing final weight and feed conversion ratio (FCR) between animals fed control (100% FM) and PBM‐supplemented FM diets using data from 47 published articles targeting 33 different species (141 and 96 effect size calculations for final weight and FCR, respectively). In addition, several analyses were performed to determine the effect of different moderators as well as variation across species. Meta‐regression was conducted to evaluate the effect of varying PBM proportions of the diet on the response variables. Overall, a non‐significant final weight but a significant higher FCR was detected with aquaculture species fed PBM diets. Similar trends in final weight were observed for subgroups. However, FCR for crustaceans and marine fish fed PBM diets was not significantly different than those fed control diets. In both freshwater and marine fish, 'species' was a significant moderator effect on responses, while the 'level of FM replacement' was significant only in marine fish. Higher between‐study heterogeneity was detected for fish, which may be due to the influence of certain factors, such as variability in nutritional quality and palatability and digestibility of PBM or due to variability on the fish meal used. In contrast, low between‐study variation was observed in crustaceans indicating consistent success in PBM‐supplemented diets for shrimp compared with fish. [ABSTRACT FROM AUTHOR]

A 120-day feeding trial was conducted in floating cages to evaluate growth performance and digestibility of Nile tilapia (Oreochromis niloticus) juveniles fed diets containing different levels of poultry by-product meal (PBM) as a replacement for fishmeal. Nile Tilapia with an average body weight of 56.6 ± 0.28 g were used in this experiment. Five diets were formulated to contain graded levels of PBM at 0%, 5%, 10%, 20%, and 30% poultry by-product meal (PBM) and are referred as PBM0, PBM5, PBM10, PBM20, and PBM30, respectively. Groups of 25 Nile tilapia were fed close to the apparent satiation, three times a day. The results showed that growth performance, survival and whole-body composition for fish fed the experimental diets were not significantly different (P >.05) than fish fed the control diet. Apparent digestibility of dry matter, protein, lipid and amino acids of fish fed the PBM20 and PBM30 were lower compared to the other treatments (P <.05). The PBM dietary levels significantly lowered total protein, high-density-lipoprotein (HDL) and cholesterol concentration. The results of this study indicated that good quality PBM can be used up to 30% in commercial diets for Nile tilapia without any adverse effect. [ABSTRACT FROM AUTHOR]

Farmers and researchers in developing countries are evaluating the use of fish meal in broiler diets due to high cost and product variability. This study evaluated the effects of replacing fish meal with either soybean meal or poultry by-product meal on broiler performance and total feed cost per kilogram of gain. Three dietary treatments were manufactured to contain soybean meal and fish meal, soybean meal or soybean meal, and poultry by-products meal. Diets were balanced for lysine and fed in mash form. A total of 900 1-day-old male Cobb 500 broilers were randomly assigned to pens with 25 chicks per pen and reared for 42 d. Overall, 42 d broilers fed fish meal diets had lower body weights (P ≤ 0.05) compared to those fed soybean meal and poultry by-products meal diets but adjusted feed conversion ratio was similar (P ≥ 0.05) for all treatments. Replacing fish meal with either soybean meal or poultry by-products meal resulted in higher body weights and average daily feed intake but similar adjusted feed conversion ratio for all birds and lower feed cost per kilogram of gain. [ABSTRACT FROM AUTHOR]

By answering the need for increasing sustainability in aquaculture, the present study aimed to compare growth, gene expression involved in appetite regulation, physical characteristics, and chemical composition of Sparus aurata fed alternative protein sources. Fish were fed ten iso-proteic, iso-lipidic, and isoenergetic diets: a vegetable-based (CV) and a marine ingredient-rich (CF) diet were set as control diets. The others were prepared by replacing graded levels (10, 20 or 40%) of the vegetable proteins in the CV with proteins from a commercial defatted Hermetia illucens pupae meal (H), poultry by-product meal (PBM) singly (H10, H20, H40, P20, P40) or in combination (H10P30), red swamp crayfish meal (RC10) and from a blend (2:1, w:w) of Tisochrysis lutea and Tetraselmis suecica (MA10) dried biomasses. The increase in ghre gene expression observed in MA10 fed fish matched with increased feed intake and increased feed conversion ratio. Besides, the MA10 diet conferred a lighter aspect to the fish skin (p < 0.05) than the others. Overall, no detrimental effects of H, PBM, and RC meal included in the diets were observed, and fish fatty acid profile resulted as comparable among these groups and CV, thus demonstrating the possibility to introduce H, PBM, and RC in partial replacement of vegetable proteins in the diet for Sparus aurata.

The effect of two experimental diets with different animal protein sources on sensory, microbiological and chemical attributes of Sparus aurata flesh stored at chilling temperatures were explored through sensory evaluation, tag-pyrosequencing of the 16S rRNA gene (V3–V4 region) and SPME–GC/MS. respectively. The 50% replacement of fishmeal by either hydrolyzed feather meal (HFM) or poultry by-product meal (PBM), did not affect the initial microbial composition of seabream. Differences were observed on spoiled fish indicating that the diet with non-ruminant processed animal protein (PAPs) in combination with the applied storage conditions affect the selection of spoilage microbiota. Minor differences were also detected in volatile compounds profile of PAP-fed seabream showing no strong effect on flesh quality of fish. This research constitutes the baseline for further investigation on the use of non-ruminant PAPs in fish diets in order for aquaculture to produce a high quality of farmed fish for the consumer. [ABSTRACT FROM AUTHOR]

Abstract The best available controlled technology for transforming the disposal of animal by-products and mortalities is rendering. Two aspects of rendering process are mentioned in this research; product quality and emissions. A model of batch cooker with temperature, pressure and agitator speed controllers was designed and developed in order to optimize the process and to investigate the effect of changes in rendering conditions on quality of poultry by-product meal and also on pollutant emissions. An electronic nose system was designed and built based on metal oxide semiconductor sensors to monitor the gases emitted from batch cooker model. Also, GC-MS was used to identify the emitted components. In order to optimize the rendering process, response surface methodology was performed on temperature, cooking time and agitator speed variables. Results showed that the temperature of 140 °C (internal pressure equivalent to about 3.2 bar), the cooking time of 45 min and the agitator speed of 20 rpm optimized the process of batch cooking to maximize the percentage of protein and minimize the percentage of fat, moisture content, energy consumption and emission of pollutants. By GC-MS analysis, about 100 compounds include hydrocarbons, volatile fatty acids, sulfur-containing compounds, alcohols, ketones, aldehydes, and furans were observed in the emission of a batch cooker model. The major groups were organic acids and amides. Principle component analysis showed the most suitable sensors for detecting unpleasant odors from rendering plants. Highlights • In order to optimize the rendering process, Response Surface Methodology was performed. • The temperature of 140 °C, the cooking time of 45 min and the agitator speed of 20 rpm optimized the process. • Electronic nose was evaluated for monitoring the emissions from poultry slaughterhouse rendering units. • Between sensors that applied, sensors named MQ9, MQ135 and MQ136 were the most appropriate sensors to detect the malodor. • By GC-MS analysis, about 100 compounds were observed in the emission of a batch cooker model. [ABSTRACT FROM AUTHOR]

A 60-day experiment was conducted to evaluate the effect of dietary fish meal (FM) replacement with poultry by-product meal (PBM) on digestive enzymes, non-specific serum enzyme activity, and serum biochemical parameters of juvenile sobaity sea bream, Sparidentex hasta, weighing 29.27 ± 0.06 g. PBM replaced 0, 15, 25, 35, 45, and 55% of dietary FM in the isoproteic (50%) and isocaloric (21 kJ g−1) experimental diets. The final body weight, percentage weight gain, specific growth rate, and protein efficiency ratio were higher in PBM15, 25, and 35 than in control, PBM45, and 55. Digestive lipase and amylase activity did not differ significantly between the dietary treatments. Significantly lower trypsin and higher chymotrypsin activity were observed at PBM55 and 45, respectively. Digestive alkaline phosphatase (ALP) increased, whereas protein apparent digestibility coefficients (ADC) decreased significantly with increasing levels of PBM above 35%. Hematocrit, hemoglobin, mean corpuscular hemoglobin concentration, serum albumin, globulin, total protein, glucose, urea, uric acid, and aspartate aminotransferase did not show any significant differences between the treatments. Serum ALP, cholesterol, and calcium were higher in PBM diets than in the control diet, whereas an inverse trend was observed in triglyceride. Protein digestibility and trypsin activity and serum biochemical indices suggest that fish meal protein could be reduced up to 45% by the inclusion PBM in the formulated diets for S. hasta juveniles without any adverse effect on its overall performance. [ABSTRACT FROM AUTHOR]

Two feeding trials examined the replacement of fishmeal (FM) with poultry by‐product meal (PBM) in the diet of juvenile Sparus aurata. In Feeding trial I (100 days), three diets were formulated, where FM protein was replaced by 50% (PBM50) and 100% (PBM100) PBM, while in Feeding trial II (110 days), four diets were formulated using the same FM control diet, but FM was replaced at lower levels: 25% (PBM25), and 25% (PBM25 + ) and 50% (PBM50 + ) with the supplementation of lysine and methionine amino acids. PBM protein can successfully replace 50% of FM protein in the diet of S. aurata without adverse effects on survival, feed intake, growth performance and feed utilization, given that the diet is balanced with lysine and methionine. The proximate composition of body and muscle was unaffected by the diet, but the total FM replacement resulted in reduced lipid and energy contents in fish. A fifty per cent FM replacement by PBM did not affect haematological parameters indicating a good fish health. Similarities in trypsin and chymotrypsin activities with FM‐fed fish suggest a high digestibility of PBM. High dietary levels of PBM reduced the liver gene expression of GH/IGF axis and of cathepsin D suppressing fish growth and modulating the protein turnover. [ABSTRACT FROM AUTHOR]

Abstract Two experiments were conducted on juvenile barramundi testing the replacement of regular poultry by-product meal (PBM) with a premium grade poultry protein concentrate (PPC). In the first experiment, a series of five iso-nitrogenous and iso-calorific dietary treatments composed of incrementally increasing levels of PPC from 0% to 20%, substituting PBM were formulated (PPC0, PPC5, PPC10, PPC15, PPC20). The diets were restrictively pair-fed to 63g barramundi for 56 days. In the second experiment, a series of four iso-nitrogenous, iso-calorific and iso-phosphoric dietary treatments composed of incrementally increasing levels of PPC from 0% to 20% substituting PBM were formulated (PPC0+P, PPC6.7+P, PPC13.3+P, PPC20+P). An additional dietary treatment was formulated without any phosphorous supplementation (PPC20-P). The diets were restrictively pair-fed to 69g barramundi and the PPC20+P and PPC20-P were also tested when fed to satiation for 42 days. Experiment 1 demonstrated a clear linear trend towards poorer growth performance and feed utilisation when increasing the level of PPC in the diet. Significant differences were noted for final weight, weight gain, SGR and FCR (P<0.05) in the fish fed diets PPC15 and PPC20 compared to the PPC0. Protein retention efficiency and the apparent biological value of protein and energy was lower (P<0.05) in the PPC20 compared to the PPC0 fed fish. The apparent digestibility of crude protein, gross energy, phosphorous and several amino acids all increased with increasing level of PPC in the diet. In experiment 2, using iso-phosphoric diets, the reverse trend was demonstrated whereby increasing PPC improved the performance of barramundi. Significant differences were noted for the final weight, weight gain, SGR and FCR (P<0.05). When comparing the PPC20+P and the PPC20-P fed fish, there was a clear negative impact of not supplementing phosphorus, which was further compounded in fish fed to satiation (interaction, P<0.05). There were no significant differences in nutrient retention with the exception of calcium which increased with increasing PPC, and energy retention being higher in fish fed PCC20+P than PCC20-P treatments. The results of these two experiments demonstrate that the effective replacement of regular PBM with high quality PPC is achievable and when the diets are supplemented with phosphorus to an inclusion >1.5%, promotes faster growth, for fish fed restrictedly and to satiation. The results indicate a pressing need to redefine the phosphorus requirement of barramundi juveniles, notably to ensure the scope for growth is not affected when testing the nutritional value of novel protein sources. Highlights • Characterisation of the nutritional value of a high quality poultry meal against standard poultry meal in barramundi • Determination of the effect of phosphorus supplementation to PPC diets on barramundi growth and nutrient retention • Empirical evidence for a much higher phosphorus requirement in juvenile barramundi compared to the published literature [ABSTRACT FROM AUTHOR]

It was evaluated the effect of DHA (extract from Aurantiochytrium sp.) inclusion in diets formulated with poultry by-product meal (PBM) using beef tallow (TALLOW) to fulfill the lipid demand in substitution of fish oil (FO) in juvenile totoaba (9.5 ± 0.1 g). With this purpose four diets were formulated to contain PBM with FO (PBM + FO positive control) or TALLOW (PBM + TALLOW negative control) and two diets containing different levels of DHA; one supplemented with 50% (PBM + TALLOW+50%DHA) and 100% DHA (PBM + TALLOW+100%DHA), based on DHA requirements for marine carnivore fish. After nine weeks, no signs of fatty acid (FA) deficiency were noticed; survival was above 92% across dietary treatments, and production performance was also similar, with exception of feed conversion ratio and viscerosomatic index. Tissues proximate composition was affected by dietary treatments. Tallow-based diets increased hepatic lipid content. However, 100% DHA supplementation adjusted this effect. Overall blood parameters were not influenced by tallow inclusion, except for triglycerides. Fish fed the PBM + TALLOW diet exhibited significant higher levels of triglycerides compared to those fed the PBM + FO diets. However, the DHA supplementation in both levels amended this effect. The FA profile in the liver and muscle tissues were affected and reflected the dietary fatty acid composition to some extent. Tallow-based diets exhibited significantly higher levels of MUFAs (e.g., 18:1n-9) and reduced levels of SFAs than those fed the PBM + FO control diet. Muscle tissue of fish fed the PBM + TALLOW diet exhibited significantly lower levels of DHA and EPA than that fed PBM + FO diet. However, DHA supplementation partially corrected this effect by enhancing DHA content in muscle. The magnitude of LC-PUFA “sparing effect” in the present study was limited due to the elevated levels of dietary 18:2n-6 from the PBM that accumulated in the muscle tissue in the extent of the LC-PUFAs. In summary, the current results provide valuable insights regarding dietary DHA in juvenile totoaba towards formulating fish oil-free diets. Dietary PBM and beef tallow successfully replaced FO in the context of production performance and overall blood parameters. DHA supplementation was beneficial for enhancing the levels of this human health-promoting fatty acid in the muscle tissue. Also, it might increase fish performance reducing the need of using fish oil in aquafeeds. We suggest that towards fish oil-free aquafeed formulations it is essential to balance the dietary fatty acids. Concomitant to this fact, it will be necessary to reduce the lipid content in PBM to facilitate feed formulation. [ABSTRACT FROM AUTHOR]