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Two novel technologically advanced high protein distiller dried grains with yeast in it (HP50Y & HP40Y) were evaluated for juvenile tilapia. This experiment assessed the nutritional potential of using high protein (40 and 50%) distillers dried grain to replace corn protein concentrate (CPC) in formulation of tilapia diets for more sustainable development of aquaculture. A 10-weeks growth trial was conducted, using nine diets formulated to contain 32% protein and 6% lipid. Each protein was included at levels (0, 5, 10, 15 and 20%) replacing CPC on protein basis. Juvenile tilapia (mean initial weight 5.23 ± 0.20 g) were evenly distributed in thirty-six, 75-L aquaria working as a recirculating system and fed twice daily to apparent satiation throughout the study. Tilapia exhibited no significant (p > 0.05) differences in growth, FCR, survival, whole-body proximate composition, mineral composition, and hematological parameters when fed HP50Y and HP40Y supplemented diets compared to the control diet. Digestibility coefficients for the test ingredients were determined in tilapia for dry matter, energy, crude protein, individual and total amino acids using 1% titanium oxide as the inert marker with 70:30 replacement strategies. All the values were found in acceptable range for the distiller grains when compared to literature. Results from this study revealed that HP50Y and HP40Y both are good alternative protein sources and can be used up to 20% inclusion level in the diets of tilapia. • CPC were replaced with HP40Y & HP50Y. • Both are good plant protein source, used up to 20% to replace CPC. • No differences were found in growth & whole-body composition of tilapia. • No differences were found in hematological parameters. [ABSTRACT FROM AUTHOR]

A 42–day trial was conducted to evaluate the performance of juvenile (0.30 g initial weight) Pacific white shrimp Litopenaeus vannamei offered diets containing various levels of copper hydroxychloride (Cu 2 (OH) 3 Cl) containing 58.8% copper (Cu) or Cu sulfate (CuSO 4 ) containing 25.5% Cu. The basal diet (360 g/kg protein, 80 g/kg lipid) was primarily composed of soybean meal, fish meal, corn protein isolate and whole wheat and was formulated to be deficient in Cu (approximately 10 mg Cu/kg). The basal diet (B10) was supplemented with 30, 90, 150, and 210 mg Cu/kg from each Cu source. With the exception of 1 treatment (H220, Cu supplemented diet with dietary copper 210 mg/kg from Cu hydroxychloride, n = 4), five replicate groups of 15 shrimp per tank (initial weight 0.30 g) were offered the test diets in slight excess. At the end of the trial, no significant differences were observed in final biomass (53.20–64.40 g), final mean weight (4.34–4.87 g), weight gain (1349–1544%), feed conversion ratio (FCR, 1.61–1.82), survival (81.3–96.0%), and thermal growth coefficient (0.082–0.087). The carapace, hepatopancreas, and whole shrimp Cu were significantly increased with dietary Cu levels from either source. No significant differences in hemolymph Cu contents were observed between the two sources. The Cu concentrations of hepatopancreas and whole shrimp were significantly lower in shrimp fed diets with Cu hydroxychloride than those in shrimp fed diets with Cu sulfate. The Cu contents of final whole body significantly increased with dietary Cu levels from either source and corresponded to a decreased trend in whole body Cu retention as dietary Cu increased regardless of source. Sequencing of intestinal and fecal microbiomes (16S V1–V3) captured distinct microbial communities based on source but not copper treatment group. However, the abundance of several specific family and genera of bacteria did appear to respond to different types and doses of dietary copper. Among these we observed a trend of decreased abundance of particular species of Vibrios , including V. harveyi , V. sinaloensis and V. orientalis . Results of this study confirm that both copper sources are utilized efficaciously by Pacific white shrimp, however, differential deposition patterns indicated the two sources of Cu are metabolized differently. Hence, additional studies to assess the specific metabolic pathways of various Cu sources as well as possible effects of high copper levels on resistance to infection should be undertaken in the future. Statement of relevance In this study, we assessed the efficacy of various levels of dietary copper supplementation with copper sulfate and copper hydroxychloride in Pacific white shrimp. Our finding shows that both copper sources are utilized efficaciously but metabolized differently by shrimp. This manuscript provides valuable information about effects of high copper levels from two copper sources in shrimp. [ABSTRACT FROM AUTHOR]

The ionic profile of inland low salinity water sources can be dramatically different with variable concentrations of magnesium (Mg2+). Inland shrimp farmers in Alabama, USA, supplement Mg2+ at the start of each production cycle to reach concentrations >20 mg/L at 1 to 11 g/L salinities. However, this concentration may not be high enough for larger shrimp in the later phase of the production cycle. Therefore, two field trials were conducted on a commercial shrimp farm in west Alabama to evaluate the effects of Mg2+ concentration in low salinity water on growth, survival, and physiology of Pacific white shrimp, Litopenaeus vannamei. In the first study, additional Mg2+ was supplemented to four production ponds (28 mg/L Mg2+) and compared with four control ponds (12.8 mg/L Mg2+). A stocking density of 27 post-larvae/m2 was used in ponds, and shrimp were offered a commercial feed twice daily. After a 23-week pond trial, whole-body Mg2+ concentrations were higher in shrimp reared in Mg2+ treated ponds, while no significant differences in other study variables were observed between pond groups. After week 15 (shrimp weight > 22 g), weekly body weights of shrimp were significantly lower in the control group compared to the elevated Mg2+ treatment. This could be due to size-dependent deficiency in the availability of adenosine triphosphate (ATP) and Mg2+ to support growth of larger adult shrimp. The second experiment was conducted to evaluate performance of larger shrimp (∼13 g initial weight) reared in two on-levee flow-through tank systems. One tank system received water from a control pond with 12 mg/L Mg2+, while the second system was sourced with water from a production pond with a higher amount of Mg2+ (37 mg/L). In each system, twelve 800 L tanks were stocked with shrimp at three different densities (24, 29, and 35 shrimp/m2) to evaluate possible interactions between stocking density and Mg2+ concentration in water. Following an 8-week tank trial, no significant effect of Mg2+ concentration, stocking density, or their interaction was observed on growth, survival, or physiology of shrimp. Overall, these results confirm that even moderate elevations in Mg2+ in low salinity water are advantageous to adult shrimp (>22 g) in later stages of the production cycle compared to post-larvae, juveniles, or sub-adult shrimp. • Increasing Mg2+ in low salinity water is advantageous to adult shrimp (>22 g) in later stages of production. • Increasing Mg2+ in low salinity water increased whole body magnesium storage in larger shrimp (>22 g). • Aqueous Mg2+ and Mg:Ca ratios are important at all stages of shrimp production in low salinity water. [ABSTRACT FROM AUTHOR]

Two eight-week feeding trials were conducted to evaluate the effect of dietary carbohydrate to lipid ratios on growth performance on juvenile California yellowtail Seriola dorsalis. In Trial 1, groups of twenty California yellowtail (ca. 6.8 g) were fed five iso‑nitrogenous diets that were formulated to contain decreasing levels of crude lipid from 21% to 6% by replacing menhaden fish oil with corn starch on a weight basis In Trial 2, groups of twenty fish (ca. 5.2 g) were fed five iso‑nitrogenous diets that were formulated using a similar matrix, corn starch 0–24% was used to replace lipids (11.3 to 1.3%) at approximately 2:1 ratio to maintain the diets with similar energy content and the nitrogen free extract (carbohydrates) from 10% to 30% of the diet Fish were fed 5–11% body weight per day over the course of both trials. Growth performance metrics including thermal-unit growth coefficients and protein retention efficiencies were measured and compared using a quadratic regression model. Fish that were fed diets containing high levels of dietary lipids (15% or higher) exhibited decreased growth performance in Trial 1. In Trial 2, fish that received diets containing the highest level of carbohydrates exhibited improved feed efficiency and overall performance. The results from both trials demonstrate that juvenile California yellowtail with a starting size of 5–7 g have an energy fraction preference and display increased growth when fed diets containing a carbohydrate to lipid ratio of up to 5.8. • California yellowtail juveniles fed diets containing up to 30% dietary carbohydrate exhibited improved feed efficiency and overall growth. • 15% lipid diets overburdened fish, with carbohydrate replacement of lipids improving overall growth performance. • Carbohydrate to crude lipid ratios as a fraction of dietary energy is important for California yellowtail feed formulations. • California yellowtail have an energy fraction preference. [ABSTRACT FROM AUTHOR]

A series of trials were designed to evaluate hydrolysates from waste streams of squid and scallop processing centers for the use in practical shrimp feeds. Towards this goal, three growth trials and a consumption trial were conducted to evaluate the use of dry hydrolysate from squid and scallop waste as specialty ingredients in commercial type feed formulations for Pacific white shrimp Litopenaeus vannamei . In the three six-week growth trials, the basal diet (35% crude protein, 8% lipid) consisted primarily of soybean meal (SBM), corn protein concentrate, corn starch, and whole wheat. In Trial 1, the basal diet was supplemented with 3%, 6%, and 9% from squid hydrolysate (Squ) or scallop hydrolysate (Sca) as well as two treatments using SBM which was impregnated with the hydrolysate prior to use. In Trial 2, the basal diet was supplemented with 3% Squ or Sca, shrimp but the shrimp were offered diets in slight excess to allow for possible increases in consumption of feeds. In Trial 3, Squ and Squid meal were compared at 6%. At the end of the three growth trials, no significant differences were found in final biomass, final mean weight, percent weight gain, feed conversion ratio, and survival. Additionally, a group of shrimp (3 g initial mean weight) were used to estimate consumption of the feeds over three 1-hour feedings over three days. Interestingly, the estimated feed intake of the basal diet was significantly higher than that of diets supplemented with 3% Squ or Sca. Results of the present study indicate that Squ and Sca as well as the SBM impregnated with Squ or Sca are good marine ingredients and can be used as feed ingredients. However, no evidence of improved feed intake or enhancement of growth were observed even though the diets were plant based. Statement of relevance In this study, a series of trials were used to assess the efficacy of dry hydrolysate from squid and scallop as well as traditional squid meal use in plant based practical diets designed for the Pacific white shrimp. These findings will be useful because the feed producers are interested in how specific produce may improve performance either as a nutrient source or attractant, particularly in diets that do not contain fishmeal. The conclusion provide valuable information that indicates feed manufacturer and researchers can use these hydrolysate products as feed ingredients in diets of shrimp, but no evidence for use of these products to improve the shrimp growth performance was observed. [ABSTRACT FROM AUTHOR]

Two 10-week growth trials and digestibility trials were conducted to assess the efficacy of various cottonseed products in practical diets for the Florida pompano Trachinotus carolinus. In trial 1, a basal diet containing 150 g/kg of fishmeal (FM150) was modified by the iso-nitrogenous replacement of fishmeal (FM) with cold pressed cottonseed flour (CSF) resulting in diets containing 100 g/kg (FM100), 50 g/kg (FM50) and 0 g/kg (FM0) of fishmeal. To determine if lysine was limiting in the FM0 diet, two additional diets were developed using a high lysine corn protein concentrate (FM0-LCPC) or a crystalline source of lysine (FM0-CL). In trial 2, the basal diet was formulated to contain 457.0 g/kg of soybean meal (SBM) and 150 g/kg of poultry by-product meal (PBM), the other three diets were made by replacing SBM on an iso-nitrogenous and iso-lipidic basis with varying cottonseed flours (CSF) which included cottonseed flour (CSF), gossypol-extracted cottonseed flour (ECSF), and glandless cottonseed flour (GCSF). In trial 1, results showed that the use of up to 196 g/kg of CSF with a lysine supplement does not inhibit growth performance of the fish. In trial 2, no significant differences were observed in growth performance of the fish maintained on the various diets. Although gossypol was detected in the livers of fish offered diets with gossypol, no differences were observed in the cells of the liver samples or organization of the liver cells amongst any of the treatments. After each growth trial, apparent digestibility coefficients for dry matter (ADMD), energy (AED), and protein (APD) were determined for primary ingredients. In the first digestibility trial, no significant differences were observed with regard to digestibility coefficients for FM, CSF, and corn protein concentrate (CPC). In the second digestibility trial, no significant differences were observed on ADMD and AED for the ingredients GCSF, CSF, and ECSF. However, the APD values for ECSF were found to be significantly lower than those values of GCSF and CSF. Results of this study provide support that cottonseed products are acceptable for use in practical diets for Florida pompano. Statement of relevance In this study, we assessed the efficacy of various cottonseed products in practical diets for the Florida pompano. These findings will be useful because the feed producers need the growth and digestibility data of the cottonseed products as an alternative ingredient to use in the diet formulation. The conclusions in this manuscript provide valuable information which researchers and feed producers need to use the cottonseed products in diets of this species. [ABSTRACT FROM AUTHOR]

Twelve ingredients obtained from new, non-genetically modified soybean cultivars as well as commercially available sources of soybean meal (SBM) were evaluated in practical feed formulations for the Pacific white shrimp, Litopenaeus vannamei , using both digestibility and growth trials. Apparent digestibility coefficients for energy (ADE) and protein (ADP) were determined using chromic oxide as inert marker and the 70:30 replacement technique. Digestibility coefficients for ADE and ADP ranged from 76.6 to 91.3% and 93.6 to 99.8%, respectively. In general, two distinct groups of high and moderate digestibility values were observed. A separate 8-week growth trial was conducted to evaluate selected SBMs using six replicate tanks per dietary treatment (10 shrimp per tank, initial weight 0.52 ± 0.04 g). An SBM-based reference diet was formulated using commercial SBM (45.3), which was then completely replaced on iso-nitrogenous basis with other experimental SBMs. Significant differences ( P ≤ 0.05) were observed in growth performance but not survival. In general, trends in digestibility values were similar to those of the growth trial. Ingredients (I)-16, I-17, I-18, and I-19 demonstrate relatively higher values in terms of digestibility as well as supporting good growth. Results indicate that genetic selection of soybean for nutritional characteristics of the meal has the potential to increase the nutritional values of SBM for shrimp feeds. Statement of relevance This study provides useful and important information of 12 varieties soybean meal in shrimp to support the aquaculture feed industry development. [ABSTRACT FROM AUTHOR]

Despite garnering high interest in fish nutrition as an essential amino acid in a number of teleosts, the metabolic and physiological functions of taurine remain poorly described in fish. This study describes the postprandial changes of taurine in Florida pompano juveniles fed a taurine-replete diet, followed by a wide screening of metabolic and physiological markers when fed a taurine-deficient diet over 16 days. The goal was to screen for markers of early taurine deficiency and identify its initial components. Postprandial taurine levels varied between 106.75 and 170.37 μg/ml with a mild peak at 2–4 h after feeding, and decreased to 72.1% of the baseline value at 6 h. Fish fed the taurine-deficient diet did not have reduced hematocrit or increased bilirubin, suggesting an absence of hemolysis. However, linear decreases in alkaline phosphatase activity and in bile acid content were observed (R 2 = 0.5968 and 0.5613, respectively, P < 0.005). Filet composition showed an overall linear increase in moisture (R 2 = 0.2666, P = 0.0338) and a marked, linear loss in lipid over time (R 2 = 0.4059, P = 0.0059). There was also a drastic, quadratic decrease in all amino acid content of the liver (R 2 > 0.75, P < 0.0001), which had decreased by 40% by day 16. Notably, levels of taurine, hydroxylysine and hydroxyproline sharply decreased and remained low. In the filet however, levels of most amino acids were not affected, except for hydroxyproline, hydroxylysine, proline, and glycine, whose levels increased significantly by day 16 while taurine levels had decreased. Serum levels were variable, and no pattern of change could be identified. Liver histology revealed marked vacuolation of hepatocytes and significant glycogen accumulation. Finally, hepatic mitochondrial proteins quadratically decreased with time (R 2 = 0.6218, P = 0.0007), paralleled with a severe linear decrease in cytochrome c oxidase (COX) specific activity (R 2 = 0.5940, P = 0.0002). This indicates that the mitochondrial electron transport chain was greatly disrupted, and which resulted in poor hepatic metabolism and production of oxidative radicals. In summary, the present study describes the first screening for metabolic and physiological biomarkers of early taurine deficiency. Although we found no evidence of overt hepatocellular damage during the course of the experiment, we observed significant alterations of cellular metabolism, especially in hepatocytes (i.e., histology, amino acid content, COX activity). Changes in serum parameters were detected, although their suitability as biomarkers will require additional research. The absence of hematocrit decrease is noteworthy in light of published literature; longer term investigations are necessary to further our understanding of taurine functions in teleosts. Statement of relevance This manuscript presents results of scientific research relevant to the field of aquaculture. Taurine is a nutrient of great importance for many teleost species and for the sustainability of fish feeds; yet its metabolic functions remain unclear. This study constitutes, to the authors' knowledge, the first attempt at characterizing these functions. These results shed light on the complexities of taurine metabolism and emphasize possible hypotheses for future research. Therefore this study presents novel research results of high interest to the aquaculture and fish biology communities. [ABSTRACT FROM AUTHOR]

The inclusion of chemoattractants has been investigated to improve the attractability and palatability of plant-based shrimp diets. A more recent approach utilizes passive acoustic monitoring (PAM) to record the sounds (clicks) emitted by shrimp during feeding activity allowing the identification of behavioral responses related to the diets. In the present study we automatically identified click signals in PAM recordings at sampling frequency of 192 kHz. This methodology was applied to evaluate the efficiency of three chemoattractants (krill meal, squid meal and fish hydrolysate) added to a basal all-plant diet on the acoustic feeding behavior and food consumption of naive (without acclimation) and non-naive (acclimated to the diets) Litopenaeus vannamei. Five diets were used: basal all-plant diet (AP, negative control) and its modifications to contain 20 g/Kg of krill meal (AP+KM), 20 g/Kg of squid meal (AP+SM) and 40 g/Kg of fish hydrolysate (AP+FH); a diet with 120 g/Kg fishmeal (FM) was used as a positive control. Ten shrimp (6.8 ± 0.6 g; mean ± SD) were stocked per aquarium (70 L) in a clear water recirculation system (30 aquaria, five diets with six replicates). The food consumption and acoustic activity were evaluated simultaneously in each aquarium over a 30-min period during two consecutive days for each trial, naive and non-naive shrimp. Strong positive relationships (r = 0.78–0.81; P < 0.001) were found between food consumption and total number of clicks emitted by naive and non-naive shrimp. Overall, the inclusion of the chemoattractants to the plant-based diet had a positive effect improving acoustic feeding behavior and food consumption for naive and non-naive L. vannamei. In particular, the response of non-naive shrimp to chemoattractants was markedly increased, and the highest clicking activity was attained by using krill meal (AP+KM), followed by fish hydrolysate (AP+FH). The new analytical method proved to be a useful alternative approach for studying shrimp feeding behavior, also indicating the potential of PAM to forecast feed intake and improve efficiency of feed management. • A novel analytical method based on click detection was applied to study shrimp feeding behavior. • Audio sampling rate (192 kHz) was double of previous studies with passive acoustic monitoring (PAM) of L. vannamei. • Chemoattractants added to all-plant diet had a positive effect on shrimp food consumption and feeding behavior. • Results reinforce the benefits of using PAM to investigate shrimp feeding activity. [ABSTRACT FROM AUTHOR]

A 9-week growth trial was performed to assess the role of indispensable (IAA) and dispensable amino acids (DAA) supplementation in diets designed for juvenile (10.6 g) channel catfish (Ictalurus punctatus). The effects on fish growth, feed utilization, proximate, amino acids (AA) composition, and morphometric indicators were followed. Nine iso-lipidic (8 %) experimental diets were formulated with different levels of intact protein (32, 30, 28, 26, and 24 IP) supplemented with IAA (Lysine and Histidine) to restore IAA balance to those stated in NRC (2011). Additionally, DAA (Glutamic acid and Glycine) were added to the 24IP at different rates (2 %, 4 %, 6 %, and 8 %). At the conclusion of the growth trial, however, there was a linear decrease in fish growth as IP was lowered from 32% to 24%. But, based on mean separation; final mean weight (g), thermal growth coefficient (TGC), and feed conversion ratio (FCR) of channel catfish were not significantly different (P > 0.05) among fish groups fed diets containing 32 %, 30 %, 28 % and 26 % IP supplemented with IAA. Fish growth was significantly reduced, while apparent net protein retention (ANPR) and FCR significantly increased as IP was lowered to 24%. While growth and FCR of catfish fed 24IP with DAA (2–6 %) were not significantly different compared to catfish fed 32 % and 30 %IP diets. In conclusion, IAA (lysine and histidine) could be used as a supplement to reduce intact protein from 32 % to 26 % in channel catfish diets with maintaining IAA balance as recommended by NRC (2011). Catfish growth was improved by fortification of the 24IP diet with DAA (2–6 %), so the dietary IP level could be further lowered to 24 % with supplementation of IAA and DAA. • The role of CAA supplementation in reducing protein in the channel catfish diet is confirmed. • Fish growth was not significantly affected by reducing protein to 26 %. • Fish fed a 24% protein diet significantly reduced growth performance. • The contribution of dispensable amino acids supplementation in a 24 % protein diet has been evaluated. • 24% protein diet with dispensable amino acids (2–6 %) improved the fish performance. [ABSTRACT FROM AUTHOR]

One of the highest priority areas for improvement in aquaculture is the development of dietary additives and formulations which provide for complete mucosal health and protection of fish raised in intensive systems. Far greater attention has been paid to dietary impact on gut health than to protective effects at other mucosal surfaces such as skin and gill. These exterior surfaces, however, are important primary targets for pathogen attachment and invasion. Flavobacterium columnare , the causative agent of columnaris disease, is among the most prevalent of all freshwater disease-causing bacteria, impacting global aquaculture of catfish, salmonids, baitfish and aquaria-trade species among others. This study evaluated whether the feeding of a standard catfish diet supplemented with Alltech dietary additives Actigen ® , a concentrated source of yeast cell wall-derived material and/or Allzyme ® SSF, a fermented strain of Aspergillus niger, could offer protection against F. columnare mortality. A nine-week feeding trial of channel catfish fingerlings with basal diet (B), B + Allzyme ® SSF, B + Actigen ® and B + Actigen ® +Allzyme ® SSF revealed good growth in all conditions (FCR < 1.0), but no statistical differences in growth between the treatments were found. At nine weeks, based on pre-challenge trial results, basal, B + Actigen ® , and B + Allzyme ® SSF groups of fish were selected for further challenges with F. columnare . Replicated challenge with a virulent F. columnare strain, revealed significantly longer median days to death in B + Allzyme ® SSF and B + Actigen ® when compared with the basal diet (P < 0.05) and significantly higher survival following the eight day challenge period in B + Actigen ® when compared with the other two diets (P < 0.05). Given the superior protection provided by the B + Actigen ® diet, we carried out transcriptomic comparison of gene expression of fish fed that diet and the basal diet before and after columnaris challenge using high-throughput RNA-seq. Pathway and enrichment analyses revealed changes in mannose receptor DEC205 and IL4 signaling at 0 h (prior to challenge) which likely explain a dramatic divergence in expression profiles between the two diets soon after pathogen challenge (8 h). Dietary mannose priming resulted in reduced expression of inflammatory cytokines, shifting response patterns instead to favor resolution and repair. Our results indicate that prebiotic dietary additives may provide protection extending beyond the gut to surface mucosa. [ABSTRACT FROM AUTHOR]

• Shrimp were sampled from the same farms pre-post processing in Thailand and Ecuador. • Patterns in the elements were evaluated statistically and through classification. • Commercial Processing with a salt brine altered the profile of shrimp from Thailand. • The altered elemental profile affected the accuracy of discriminant analysis. Commercial processing is potentially a confounding factor for elemental profiling in shrimp. Here, two sets of paired samples were collected pre/post-processing from the same farms; one set from Thailand (n = 15) and one from Ecuador (n = 19). The samples from Ecuador were subjected to a meta-bisulfite bath as part of the processing regimen while the samples from Thailand were subjected to a salt bath. The elemental concentrations were determined via ICM-MS. Elements reported are of Al, As, Ba, Ca, Ce, Co, Cr, Cs, Cu, Fe, K, Li, Mg, Mn, Mo, Na, Nd, Ni, Rb, Se, Sr, Y, and Zn. Elements from samples in Ecuador were unaffected by the processing regimen (MATS = 15.47, p = 0.3), but samples from Thailand (MATS = 766.29, p = < 0.001) were. The pre/post-processing samples were classified to country of origin with a training model of samples from shrimp farms in five countries. Samples that were post-processing were less accurately classified (58 % vs. 68 % accuracy) compared to pre-processed samples. Samples from Ecuador had high fidelity regardless of processing while the samples from Thailand were less accurately classified. This study shows processing can alter the elemental profile in shrimp muscle tissue, and may impact the accuracy of classification. [ABSTRACT FROM AUTHOR]

Abstract: The present study aims to identify the limiting amino acids in low fish meal, soy-based diets in juvenile white seabass. Two 8-week trials were conducted. The first trial evaluated three diets containing 36, 18 and 9% fish meal in the diet (FM36, FM18, FM9, respectively), with the last two diets being supplemented with methionine and taurine. In the second trial, seven diets were formulated, including a high (36%) fish meal diet (HFM, similar to FM36) and five diets with medium (18%) fishmeal levels. These included an unsupplemented diet (MFM) and four with increasing levels of methionine (+M, +2M) and taurine (+2MT and +2M2T) supplementation. An additional diet was formulated with soy protein and poultry by-product meal to completely replace fish meal (PM). In trial 1, fish fed the FM18 diet grew significantly faster than fish fed the FM36 and FM9 diets. In trial 2, fish fed the +2M2T diet grew better than fish fed any other diets, and feed efficiency was highest in fish fed the +2M2T and PM diets. Fish fed the unsupplemented MFM diet had the lowest growth and feed efficiency. Methionine supplementation (+M and +2M) had a limited but significant effect on growth performance compared to MFM-fed fish. Fish fed the PM diet showed similar growth as those fed the +2MT and commercial diets, but was lower than +2M2T diet. Across both trials, growth rate was highly correlated with dietary taurine, except in diets containing less than 18% fish meal, i.e., diets PM and FM9. Both of these diets had equivalent or superior dietary taurine levels compared to diets +2M2T and FM18, but resulted in significantly poorer growth. This suggests that taurine is the first-limiting nutrient in feeds containing at least 18% fish meal while methionine was marginally deficient. In diets containing lower levels of fish meal however, methionine and taurine supplementation is ineffective; hence another (undetermined) nutrient became first-limiting. Additional research is necessary to identify this limiting nutrient, as well as determine the specific taurine requirement of WSB. [Copyright &y& Elsevier]

Abstract: In the United States, catfish industry is a mature industry with a long history of success. However, the industry faces numerous challenges while it evolves and adapts to shifting inputs and market demands, such as the dramatic increase in the price of feed ingredients and requests for more consistent fillet color. There is considerable interest in reducing the cost of production diets either by reducing the protein content or by using alternative ingredients such as corn gluten feed. Towards this goal, a pond study was conducted to evaluate the utilization of alternative feed containing 20% corn gluten feed compared to traditional feed without corn gluten feed for the production of channel-blue hybrid catfish. Both alternative and traditional feeds were formulated with two protein contents (28% and 32%). In addition to traditional parameters, the xanthophyll contents on the fish fillets were determined. Upon initiation of the pond trial, 600 hybrid catfish fingerlings were stocked in each of 20 0.04-ha ponds, with a mean weight of 34.5g/fish. Fish were fed four experimental diets once daily to apparent satiation over a summer growing season. No significant differences were found in growth performance and feed utilization among the four treatments, including gross and net yield, total amount of feed fed, estimated feed conversion ratio and survival. No significant differences were found in mean individual fish weight and mean total body length at harvest, relative weight index and dressout (headed and gutted). However, intraperitoneal fat ratio was significantly lower in fish fed the alternative feeds indicating lower energy content of the diet. No significant differences were observed in hematology and immune response indices. Xanthophyll levels in diets and in fillet were linearly related, but without discernible yellow color. These data generally indicate that channel-blue hybrids can efficiently utilize all the four experimental diets with satisfying production result. [Copyright &y& Elsevier]

Provenance of seafood items is a concern for consumers and importers alike. Elemental profiling has been put forth as a potential tool to improve seafood traceability. Whiteleg shrimp Litopenaeus vannamei collected from farms in Ecuador, India, Indonesia, Vietnam, and Thailand were classified to country of origin based on element concentrations in muscle tissue. Shrimp were dried, digested, and analyzed via ICP-MS. Out of the 41 elements investigated, 33 are reported as being above detection limits. Twenty-eight elements were statistically different across countries, and of these 28, Ecuador had unique group membership in 7. A random forest classification model utilizing 16 elements had an overall accuracy of 91% of correctly classified samples to country of origin. A canonical discriminant analysis was conducted to understand the variation in the data and identify elements that were important to differentiation in multi-dimension space. Elements identified as important contributors were Al, As, B, Ca, Co, Cs, Sr, and V. This study shows that shrimp from Ecuador tend to be more mineralized than shrimp from Asia, and classification models can discern samples from these countries successfully. This demonstrates the potential of a traceability database for cultured shrimp products from predominant production countries. • Shrimp from 5 countries were collected from farms for elemental analysis. • Trace elements classified shrimp in discriminant analysis with 91% accuracy. • Ecuadorian shrimp have a unique profile compared to Asian shrimp. • This study provides further evidence for elemental profiling as a traceability tool. [ABSTRACT FROM AUTHOR]

Florida pompano, Trachinotus carolinus is positioned to be an important fish species in US mariculture. If commercial production is to be developed sustainably and with reduced feed costs, it is critical to maximize the level of plant-based proteins in the diet. Thus, an understanding of limiting amino acids is necessary to properly formulate grow out feeds, which include lysine. This work was conducted using eight diets formulated with graded levels of lysine (1.42–2.42% dry weight) and fed to juvenile pompano (mean initial weight 13.07 ± 0.46) for 56 days. Dose responses and significant effects were observed in final weight (FW), percent weight gain (PWG), thermal growth coefficient (TGC) and feed conversion ratio (FCR). Significant differences in mean fish whole body amino acids were observed in aspartic acid, glutamic acid, hydroxyproline, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tyrosine and valine. Regression models, such as broken-quadratic model (BQM), 4-parameter saturation kinetic model (4-SKM), 5-parameter saturation kinetic model (5-SKM), one-slope broken line model (BKL.1) and two-slope broken line model (BKL.2) from R were fitted against different parameters to determine the dietary lysine requirement. Thermal growth coefficient was the parameter utilized to fit a 4-SKM model and determine the quantitative lysine requirement. Based on these results, a minimum lysine requirement of 1.67% dry weight is recommended to meet nutritional requirements for growth in practical feed formulations. • Eight test diets were formulated with graded levels of lysine (1.42–2.42% dry weight). • A four-parameter saturation kinetic model was selected to quantify the lysine requirement. • Thermal growth coefficient was the growth parameter utilized for the lysine requirement. • Florida pompano require a minimum dietary lysine requirement of 1.67% dry weight. [ABSTRACT FROM AUTHOR]

As the ethanol industry matures and adopts new technologies, the co-products produced are also changing with their composition adjusted to meet feed industry needs. High protein distillers dried grain with yeast (HP40Y) is a relatively new product which is a variant of distillers dried grains that could be used as an improved protein source in catfish feed formulations. To evaluate the efficacy of HP40Y, a 10-weeks growth trial was conducted on the growth performance of juvenile catfish, Ictalurus punctatus (mean initial weight 1.80 ± 0.05 g). In the growth trial, graded levels of HP40Y (0.00, 3.10, 6.20 and 9.30%) were used to replace poultry meal (PM: 6.0, 4.0, 2.0 and 0.0%) and other series of diets were used with HP40Y (5.0, 10.0, 15.0, 20.0, 30.0 and 40.0%) to replace soybean meal (SBM: 51.00, 46.49, 41.90, 37.40, 28.20, 19.20%). Analysis of Covariance (ANCOVA) indicated a significant interaction between replaced protein (PM and SBM) and the inclusion level of HP40Y (up to 20%) on biomass, mean final weight, weight gain, and FCR (P < 0.05) of catfish. Therefore, the two sets of diets were analyzed separately. One-way Analysis of Variance (ANOVA) followed by Tukey multiple comparison test was used to detect significant differences between treatment means while regression analysis was used to determine the relationship between HP40Y inclusion level in the diet and weight gain and whole-body protein level of fish. In PM replacement series, complete replacement of PM with HP40Y in diet PDG9 resulted in poor performance, indicating a possible nutritional deficiency when the animal protein was removed. As a replacement for SBM, increasing levels of HP40Y only resulted in reduced growth of catfish when included in the diet at 30 and 40%. Results indicate that HP4Y is a good protein source when used at levels less than 30% of the diet. • HP40Y was replaced with soybean meal (SBM) and poultry meal (PM). • Complete replacement of PM resulted poor performance. • HP40Y is good plant protein source, used up to 20% to replace SBM. • No differences were found in protein, fat content and ash of body composition. [ABSTRACT FROM AUTHOR]

Increasing availability of automated systems and technological solutions have been one of the most important trends in aquaculture nutrition for the past few decades as the industry focuses on improving feeding strategies through highly efficient automatic feeding technologies. Monitoring of aquatic animals is not a new practice but for the last few decades aquaculture has used feeding behavior monitoring as a tool to develop efficient demand feeders. While there are many devices available for the fish production sector, many rely on visual monitoring of individuals or populations, which disable its application in most shrimp production systems. However, production of sound by the mandibular occlusion has led to the study of passive acoustic monitoring of feeding behavior in shrimp and the development of passive acoustic demand feeding systems. While this technology has been available for less than a decade it has already been validated and adopted by the shrimp production industry. It is expected to continue being improved as more data is collected on both acoustic profiling and feeding algorithms. The objective of this publication is to present a detailed review of the information available so far about acoustic profiling of shrimp, the results of the application of this acoustic feeding system in production systems, discussing the limitations of this technology and what components could be improved in the future. • Adequate demand feeders improve production efficiency in aquaculture. • Acoustic demand feeders have become popular in shrimp production. • Feed properties impact acoustic patterns. • Experimental and production data helped identify areas for improvement. [ABSTRACT FROM AUTHOR]

The culture of channel catfish, Ictalurus punctatus, is an established industry in many areas of the southern United States. Improvements in feeding regimens would economically benefit producers. The present research was designed to evaluate the effect of feeding time (AM vs PM), feeding frequency (one vs two times a day) and intermittent fasting (6 days of feeding, 1 day of fasting) on production, feed conversion ratio (FCR), survival, weight-length relationship, percent dressout (headed and gutted carcass per unit live weight), and body composition of channel catfish reared in earthen ponds. Treatments consisted of: (1) feeding catfish once daily to satiation at 0800; (2) feeding catfish once daily to satiation at 1800; (3) feeding catfish twice daily at 0800 and 1800; and (4) feeding catfish once daily at 0800 for six consecutive days followed by one day of fasting. Twenty 0.04-ha ponds were stocked with 135 sub-market (average size: 182.6 g/fish) catfish and 600 fingerlings (average size: 18.2 g/fish) resulting in a total density of 18,375 fish/ha. Each treatment was assigned to five ponds at random. Fish in all treatments were offered a commercial floating catfish diet. A portion of the marketable catfish were harvested in mid- summer and the ponds completely harvested in the fall. Production parameters (e.g., biomass, weight gain, FCR, and survival), percent dressout, and weightlength relationship of catfish did not differ among the four treatments (P > 0.05). Percent dry matter and percent lipid of the fillet of fish fed once daily at 0800 seven days a week were significantly higher than those of fish in all other treatments (P ὅ 0.05). The percent crude protein of the fillet of fish fed once daily at 1800 seven days a week was significantly higher than fish fasted one day a week (P≤0.05). These results indicate that as long as the fish are fed to apparent satiation there is no advantage to multiple feedings, to feeding at a specific time of day, or to intermittent fasting in earthen ponds. [ABSTRACT FROM PUBLISHER]

The influence of dietary lipid level on growth, survival, and proximate composition of juvenile redclaw crayfish was evaluated during a 12-week growth trial utilizing semi-intensive culture conditions. Four diets were formulated to be isoenergetic (17.58 kJ g−1) and isonitrogenous (30% crude protein). Three of the diets were designed to contain 4.2% (L4), 8.2% (L8) and 12.3% (L12) lipid in a 1:1 ratio of corn oil/fish oil. A fourth diet was formulated to contain 8.7% (LC8) lipid, with corn oil as lipid supplement. A fifth treatment (UF) was included in which the redclaw were not fed in order to estimate the contribution of primary production. Juvenile redclaw (4.08±0.2 g initial weights) were stocked at a density of 10 per tank in 15, 2.5-m3 fiberglass tanks with three replicates per treatment. The trial was conducted in an outdoor flow-through water system. The redclaw in the unfed treatment gained 8.3 g whereas redclaw that received a prepared ration gained an average of 31.9 g. Hence, in this experiment natural productivity contributed about 26% of the weight gain of the redclaw maintained in outdoor tanks. Among the fed treatments, there were no significant differences in survival, final weight, growth, or feed utilization. The hepatosomatic index (HI) generally increased with lipid level and was influenced by the sex of the redclaw. Results indicated that in similar culture conditions, diets containing 4% lipid are sufficient for redclaw growth and survival when natural food is present. [Copyright &y& Elsevier]

Four growth trials were conducted to evaluate the effects of fishmeal replacement with various levels of soybean meal (SBM) and poultry byproduct meal (PBM) on growth performance in practical diets for juvenile and sub-adult red snapper, Lutjanus campechanus. In addition, the need for taurine and palatability enhancement (krill meal) were evaluated in the high SBM, low fishmeal diet. Across the trials, ten diets were formulated to contain 36% protein and 10% lipids. All diets except for one included a taurine supplement of 1%. A supplement of 5% krill meal was added as an attractant to one of the low fishmeal and high SBM diets to explore potential palatability issues associated with plant-based proteins. No statistically significant differences were found between the performance of the basal diet and the PBM replacement diets, indicating that PBM is a suitable replacement for fishmeal in red snapper diets. On the contrary, a clear negative linear relationship was observed with increasing levels of SBM replacement. The reduced growth performance of high SBM inclusion diets is unlikely to be due to palatability issues, as no significant difference was observed between the performance of the high SBM diet with krill meal and an identical diet without krill meal. The significant reduction in growth observed in snapper fed a diet lacking a taurine supplement indicates that red snapper have a taurine requirement that is limiting at low (0.2%) levels. Gut samples were taken from fish that received the SBM diets to determine if reduced growth performance could be attributed to inflammation. However, no statistically significant difference was observed, indicating that reduced growth was not necessarily the result of a hypersensitivity reaction. Further investigation will be necessary to determine the optimal taurine requirement and required dietary supplements to improve the performance of low fishmeal feed formulations. • Fishmeal was replaced with soybean meal (SBM) and poultry by-product meal (PBM). • 100% fishmeal replacement with PBM showed no difference in growth of red snapper. • Negative linear relationships between growth and increasing levels of SBM in diets • The addition of krill meal as an attractant did not improve growth performance. • Red snapper have a taurine requirement. [ABSTRACT FROM AUTHOR]

An 8-week indoor experiment was conducted to study the effect of culturing the Pacific white shrimp in "biofloc" and "synbiotic" type system on the growth and immune responses of the shrimp. The experimental system consisted of 24 static indoor circular polypropylene tanks (800 L water volume). Each of the twenty-four tanks were stocked at a density of 125 shrimp/m2 and eight treatments with 3 replicates were assigned using a 4 × 2 factorial design. Four primary treatments included biofloc (T1), synbiotics with β-xylanase enzyme (T2), synbiotics without enzyme (T3), and a control (T4). These were further assigned to have or not have a small, fluidized bed biofilter. The mean initial weight of the shrimp stocked in the treatments with biofilter was 0.39 ± 0.02 g, while the mean initial weight in the treatments without biofilter was 0.84 ± 0.01 g. The growth performance of the whole data set was analyzed by two-way ANCOVA, using the four treatments (T) as the first main factor, the biofilter (B) as the second main factor, and the initial weight as covariable. The results from two-way ANCOVA identified significant differences between treatments in final weights, weight gain, TGC, and FCR with shrimp reared with biofloc management performing the best. In contrast, there was no significant differences in survival (%) of the shrimp cultured between the four treatments. The levels of metabolic enzyme like Alkaline phosphatase (ALP) and Alanine aminotransferase (ALT) were significantly lower in the biofloc and synbiotic with enzyme, indicating better physiological performance in terms of improving of digestive enzymes giving a better growth index. Gamma-Glutamyl Transferase (GGT) was not significantly different. In addition, the cholesterol (CHOL) level of the hemolymph was significantly higher in shrimp produced from the biofloc and synbiotic treatments. A higher level of total haemocyte count (THC) was noted in the shrimp reared in the biofloc and synbiotic treatments as compared with control, however, there was no significant differences between treatments. All treatments produced good survival, rapid growth, low FCR and physiological parameters indicating all are viable options. Consequently, the choice of how to manage the bacterial community should be based on the available resources. • Final weights, WG, and FCR of shrimp reared with biofloc performed the best. • ALP and ALT of the haemolymph were lower in the biofloc and synbiotic treatments. • Culturing the shrimp in biofloc did numerically increase the Total Haemocyte Count. • No differences were found in protein, fat content and ash of shrimp body composition. [ABSTRACT FROM AUTHOR]

Shrimp aquaculture has been on a growing trend for the past four decades and its continued success will rely on efficient feeding protocols and reductions in labor cost. Various studies have demonstrated better growth and feed conversion for shrimp fed numerous meals in opposition to the traditional 1 to 4 meals offered during the day. With the adoption of automatic feeding systems by the shrimp industry not only can more feedings be delivered but also the time of day when feed is delivered is less problematic. This opens the door to looking at various feed management strategies. The goal of this work was to continue the development of a standard feeding protocol for timer feeders (SPTF) to maximize growth rates and production efficiency in semi-intensive pond production of shrimp through manipulation of feeding schedules. For this work, a 13-week pond production trial was performed in 16, 0.1 ha outdoors ponds, stocked at 35 shrimp/m2. Four treatments including: three fixed feeding treatments based on SPTF Day, SPTF Night and SPTF 115% 24 h were offered using automatic timer-feeders, and a fourth on demand treatment utilized AQ1 acoustic feeding system. To further evaluate different combinations of number of meals, feed quantities and time of feeding, a 11-week growth trial was conducted in 32, 800 L circular tanks in a recirculating green-water system. Results for the pond trial further confirm higher yields with AQ1 acoustic feeding system and showed no statistical differences among timer feeder treatments. Results in the tank trial indicated a relationship between growth response to increasing feed inputs and number of meals rather than feeding schedule alone. We also observed in the same trial a positive response on growth to more meals for identical feeding rates. Results confirm that increasing the number of feeding allows increased feed inputs and thus increased growth. The on demand feeding protocol using passive acoustics, resulted in the best performance of the shrimp. • Feeding schedules for timer feeder feeding protocols in shrimp production. • Shrimp did not grow better when fed during a specific schedule. • Automated feedback systems still outperform improved protocols for timer feeders. [ABSTRACT FROM AUTHOR]

The inclusion of feeding effectors in plant-based diets is a strategy to accelerate feed detection and consumption by shrimp. This study evaluated the effect of krill meal (KM), krill oil (KO) and fish hydrolysate (FH) addition to a soybean-based diet on feeding behavior and growth of Litopenaeus vannamei. Ten diets (360 g/kg crude protein) were formulated including FH, KM and KO at 0, 10, 20 and 40 g/kg levels named as: Basal (0); FH10 (10 g/kg fish hydrolysate), FH20 (20 g/kg fish hydrolysate), FH40 (40 g/kg fish hydrolysate); KM1 (10 g/kg krill meal), KM20 (20 g/kg krill meal), KM40 (40 g/kg krill meal); KO10 (10 g/kg krill oil), KO20 (20 g/kg krill oil) and KO40 (40 g/kg krill oil). A growth trial was performed using twenty shrimp (0.15 ± 0.01 g) stocked per 100 L glass aquaria (four replicates/diet) in an indoor clear water recirculation system (4.2 ppt, 28 °C). Animals were fed the experimental diets four times a day for six weeks. At the end of the trial all animals were counted and weighted. Following, 300 animals (3.93 ± 0.35 g) were aleatory selected and transferred back to the system (10 shrimp/aquaria). Three replicates were used per treatment (ten diets) for feed intake and acoustic feeding behavior analysis. The food consumption and feeding activity sounds were recorded simultaneously in 30 min intervals during five consecutive days. All feeding effectors at the inclusion levels tested significantly increased L. vannamei food consumption and the passive acoustic monitoring indicated that shrimp ate faster and for longer periods of time. Food consumption was significantly higher in the treatments KM20, KM40 and KO40. The addition of feeding effectors also enhanced shrimp growth performance and significantly better values of biomass, final weight, and food conversion ratio were observed in the treatment KM40. Weight gain (%) was significantly improved only in shrimp offered KM40, KO20 and KO40 diets. It is concluded that KM, KO and FH can stimulate food consumption of soy-based diet by L. vannamei from 10 g/kg addition while the amount of food consumed and growth has been shown to be in general dose-related, although in a different way, for each type of feeding effector. • Addition of feeding effectors in soy-based diet improve feeding activity. • Food consumption and growth is dose-related for each type of feeding effector. • A dietary supplementation with 40 g/kg krill meal promotes higher shrimp growth. • Feeding effectors trigger shrimp to eat faster and for longer time. • PAM is a useful tool to evaluate the effects of feeding effectors on feeding behavior. [ABSTRACT FROM AUTHOR]

A 70-day trial was conducted to evaluate the effect of dietary protein matrix (soybean meal or poultry byproduct meal-PBM) on taurine efficacy and retention in juvenile white seabass Atractoscion nobilis. Diets were formulated to contain 40% protein and 12% lipids with taurine supplementation ranging from 0 to 1.37% taurine. Fish were fed 4–8% body weight/day over the course of the trial. Growth performance metrics and taurine retention in fish were measured and compared using a linear regression model with diet type as covariates (growth parameters) or a quadratic model with diet type as covariates (taurine retention and deposition). Fish fed diets with soy proteins had lower percent gain, survival, feed fed/fish, and thermal-unit growth coefficients (TGC) at similar levels of taurine inclusion when compared to diets with primarily PBM as the protein source. Taurine level was positively correlated with mean final weight, weight gain, percent gain, TGC of fish regardless of diet, and negatively correlated with FCR regardless of the diet. A taurine requirement based on whole-body deposition was calculated to be 1.18%, 1.21%, and 1.03% for all diets, PBM diets, and soy diets, respectively. These results demonstrate that the protein source did not influence the taurine requirement and suggest that taurine deficiencies are not the driver of lower TGC or survival in white seabass fed diets with soy, and that other factors warrant investigation. • White sea bass (WSB) were grown with varied taurine levels • The taurine requirement was lower in soy diets than poultry meal diets • There was no evidence of a conditional taurine requirement in WSB fed soy proteins [ABSTRACT FROM AUTHOR]

A series of feeding trials were conducted to investigate the absorption rate of amino acids and compare the absorption of different methionine (Met) sources in the hemolymph of Pacific White shrimp, Litopenaeus vannamei. In trial 1, a basal diet was supplemented with three alpha amino acids including DL-Met, lysine and arginine and the beta amino acid taurine. Shrimp were fed with test diets for 30 mins and then the leftover feeds were withdrawn. The hemolymph samples were taken every 30 mins over 5 h after feeding to determine amino acid (AA) concentrations in the hemolymph. Results indicated that total AA, Met and Lys were near their peak after feeding 30 mins and the level declined within 60 mins to near fasting levels. No secondary peaks were observed for any AA. The diet supplemented with AA exhibited higher peaks than the basal diet. The second and third trials focused on the identification of different patterns that would indicate asynchronous absorption and comparison of the absorption of different Met sources. Four experimental diets were produced, including a basal diet (soy protein-based), a DL-Met-supplemented, a dipeptide Met (Met-Met)-supplemented, and a high fishmeal diet (high-Met intact protein) in trial 2. Fasted shrimp were offered diets for 15 mins and then the leftover feeds were removed. The hemolymph samples were taken every 15 mins over a 1 h period after feeding. The results generally confirmed the fast absorption and clearance of AA in shrimp and indicated that the diets containing different Met sources resulted in higher Met levels in the hemolymph as compared to the basal diet. To better define the absorption process and confirm if there may be a synchronous peak during absorption, the third trial simply looked at the uptake of AA over a 1 h period with basal diet and dipeptide Met diet. The shrimp were offered diets for a total of 60 mins during this timeframe intermittent samples were taken at 0, 5, 10, 15, 20, 30, and 60 mins. Results demonstrated the pattern for AA uptake is similar with a clear upswing in AA levels in 10–15 mins after the initiation of feeding. Based on both absorption and clearance patterns of the amino acids, we demonstrated that there were no indications of asynchronous absorption of supplemented amino acids; hence, supplemented amino acids are available for metabolism. In addition, the data also demonstrated higher peak of Met over time in the hemolymph of L. vannamei with the Met-Met supplemented diet versus the DL-Met supplemented diet. • Amino acid (AA) uptake pattern is similar with a clear upswing in AA levels in 10-15 min after shrimp initiation feeding. • No indications of asynchronous absorption of supplemented AAs was observed, so crystalline AAs are available for shrimp. • This study provided evidences for higher biological efficiency observed in the previous studies for Met-Met vs. DL-Met. [ABSTRACT FROM AUTHOR]

Passive acoustics monitoring (PAM) is an exceptional tool to analyze the feeding behavior of shrimp, as they emit a "click" sound by the mandibular occlusion. Hence, acoustic demand-feeding systems based on the click signals energy have been applied to improve feeding management in shrimp farming. These acoustic signals may be affected by the texture properties of the foods pellets, which are modified by the manufacturing process. The aim of the present study was to evaluate the acoustic activity of Litopenaeus vannamei fed pelleted and extruded diets. Two commercial diets were used, manufactured by extrusion and pelleting processing with similar formulation (36% crude protein) and pellet diameter. Acoustic evaluation was performed with these diets offered "as is" dry and previously soaked in water for one and two hours in a 2 × 3 factorial arrangement. The pellet hardness and moisture content were also measured. The acoustic trial was performed using omnidirectional hydrophones inside acoustic foam anechoic chambers. Three fastened shrimp (10 g) were placed inside acoustic chambers and audio recordings started (30 min) when food (0.5 g) was offered. The texture of diets was closely related to the acoustic intensity (Root Mean Square Amplitude - RMS) produced by L. vannamei during the feeding activity. The greater hardness of the extruded diet resulted in higher RMS than pelleted food when offered dry, which could be an advantage for the sound detection of feeding activity. The lower RMS observed when both diets were soaked suggests that softer texture pellets can be eventually ingested without the need of mandibles occlusion, and consequently without clicking sound emission. Additionally, unusual clicks train signals were first reported when shrimp fed soaked diets, probably due to mandibles rubbing. The relationship between textural properties and acoustical responses of foods should gain more attention, especially considering the potential applications on automatic acoustic feedback systems in shrimp farming. • Clicking sound was not influenced by different combinations of diets and times. • Click train signals were described for penaeids, probably due to mandibles rubbing. • The texture of diets was closely related to acoustic intensity of feeding activity. • The greater hardness of extruded diet could be an advantage for the sound detection. • Results have potential applications on automatic feedback systems in shrimp farming. [ABSTRACT FROM AUTHOR]

The continued success of shrimp farming will rely on improved feed management and reductions in labor costs. Shrimp are omnivorous, eating many small meals with limited stomach capacity for food storage. Hence, increased performance may be obtained by spreading feed through multiple meals. Initial work has demonstrated that moving from two feeding per day into multiple feeding systems increases growth rate and production. Further advances have been made with on-demand (satiation) feeding systems. The goal of this work was to continue the development of standard feeding protocol's (SFP) for automatic feeding systems to maximize growth rates in semi-intensive pond production of shrimp, Litopenaeus vannamei. For this work a 13-week pond production trial was performed in 16, 0.1 ha outdoors ponds, stocked at a 26 shrimp/m2, and fed 1.5-mm 40% crude protein for the first four weeks, and 2.4-mm protein soy optimized feed (35% crude protein) for last nine weeks, both produced by Zeigler Inc. Four treatments including: three fixed feeding treatments of 130, 145 and 160% of a SFP (SFP + 30%, SFP + 45%, SFP + 60%, respectively) were offered using automatic timer-feeders, and a fourth treatment utilized on-demand AQ1 acoustic feeding system. No statistical differences were found between treatments for survival (ranging 75.2–81.4%) and FCR (ranging 0.96–1.11). In general, increased feed inputs resulted in higher production. The best response was with the AQ1 system which adjusted feed inputs in real time and ended up offered higher feed inputs resulting in larger shrimp and yields. Based on results of this work and previous trials, standard feeding protocols for automated systems can be developed but to date, automated feedback systems which operate in real time out perform the standardized practices. • Improved standard feeding protocols for production of shrimp, Litopenaeus vannamei. • Timer feeders protocols allow higher growth rates. • Automated feedback systems still outperform improved protocols for timer feeders. [ABSTRACT FROM AUTHOR]

A 10-week growth trial was conducted to optimize the amino acid (AA) profile of diets offered to Nile tilapia. Nine diets with different AA profiles were formulated to evaluate the response of this species to the shift of dietary AA profiles. A diet containing 30% crude protein, supporting the highest growth rate of fish in previous work, was used as a reference diet (30AAR), while a 24% crude protein diet (24AAR), which previously induced growth depression, was used as a basal diet. This diet contained 22.2% crude protein derived from intact proteins and 1.8% from crystalline AAs (CAAs). All of the indispensable AAs (IAAs) in the 24AAR diet were then enhanced to match levels of the 30AAR diet to confirm potential limitation of IAAs (24AAE). Dispensable AAs (DAAs) were after that incorporated at 4% of the diet to elucidate their role in the low protein diet (24AAE + N). Finally, to confirm possible limitations of one of the AA (Trp, Ile, Arg, His, Val) these IAAs were individually dropped from diet 24AAE + N. Results indicated that supplementation of DAA in the lower protein diet is needed to overcome limitations of nonspecific nitrogen and optimize protein efficiency. Growth performance of fish fed diets without DAA supplementation was not comparable to those of fish fed diets supplemented with DAA in spite of their IAA supplements up to an IAA profile of the reference diet. In our ingredient matrix, Val is likely limiting and the supplementation of this IAA is needed to improve the performance of fish. • The study was conducted using Nile tilapia to evaluate the response of Nile tilapia to the shifts of dietary AA profiles. • The results indicated that the presence of DAA in the lower protein diet is needed to overcome limitations of nonspecific nitrogen and optimize the protein efficiency. • In our ingredient matrix, Val is likely limiting and the supplementation of this IAA is needed to improve the performance of fish. [ABSTRACT FROM AUTHOR]

Channel catfish (Ictalurus punctatus) and Nile tilapia (Oreochromis niloticus) are two aquaculture species of great importance. Intensive production is often hindered by poor growth performance and disease mortality. The aim of this study was to evaluate the potential of a commercial fermented yeast product, DVAQUA, on channel catfish and Nile tilapia growth performance metrics and disease resistance. Channel catfish and Nile tilapia were fed practical diets supplemented with 0%, 0.1% or 0.4% of DVAQUA over approximately 2-month feeding periods in recirculation aquaculture systems. To assess the potential of the postbiotic against common aquaculture pathogens, juvenile catfish were subsequently challenged by immersion with Edwardsiella ictaluri S97-773 or virulent Aeromonas hydrophila ML09-119. Nile tilapia juveniles were challenged by injection with Streptococcus iniae ARS-98-60. Serum lysozyme activity, blood chemistry and growth metrics were measured at the end of the feeding period, but no differences were observed across the different metrics, except for survival. For the pathogen challenges, there were no differences in endpoint mortality for channel catfish with either pathogen (p > .05). In contrast, Nile tilapia survivability to S. iniae infection increased proportionally to the inclusion of DVAQUA (p = .005). Changes to sera lysozyme activity were also noted in the tilapia trial, with a reduction of activity in the fish fed the 0.4% DVAQUA diet compared to the control diet (p = .031). Expression profiles of proinflammatory genes and antibodies were also found to be modulated in channel catfish fed the postbiotic, indicating some degree of protective response. These results suggest that this postbiotic may be beneficial in protecting Nile tilapia against S. iniae infection by influencing immune parameters and additional research is needed to evaluate the potential of this DVAQUA for improving catfish health and disease control., (© 2024 John Wiley & Sons Ltd.)

Biofloc technology is a rearing technique that maintains desired water quality by manipulating carbon and nitrogen and their inherent mixture of organic matter and microbes. Beneficial microorganisms in biofloc systems produce bioactive metabolites that may deter the growth of pathogenic microbes. As little is known about the interaction of biofloc systems and the addition of probiotics, this study focused on this integration to manipulate the microbial community and its interactions within biofloc systems. The present study evaluated two probiotics (B. velezensis AP193 and BiOWiSH FeedBuilder Syn 3) for use in Nile tilapia (Oreochromis niloticus) culture in a biofloc system. Nine independent 3785 L circular tanks were stocked with 120 juveniles (71.4 ± 4.4 g). Tilapia were fed for 16 weeks and randomly assigned three diets: a commercial control diet or a commercial diet top-coated with either AP193 or BiOWiSH FeedBuilder Syn3. At 14 weeks, the fish were challenged with a low dose of Streptococcus iniae (ARS-98-60, 7.2 × 10 7  CFU mL -1 , via intraperitoneal injection) in a common garden experimental design. At 16 weeks, the fish were challenged with a high dose of S. iniae (6.6 × 10 8  CFU mL -1 ) in the same manner. At the end of each challenge trial, cumulative per cent mortality, lysozyme activity and expression of 4 genes (il-1β, il6, il8 and tnfα) from the spleen were measured. In both challenges, the mortalities of the probiotic-fed groups were significantly lower (p < .05) than in the control diet. Although there were some strong trends, probiotic applications did not result in significant immune gene expression changes related to diet during the pre-trial period and following exposure to S. iniae. Nonetheless, overall il6 expression was lower in fish challenged with a high dose of ARS-98-60, while tnfα expression was lower in fish subjected to a lower pathogen dose. Study findings demonstrate the applicability of probiotics as a dietary supplement for tilapia reared in biofloc systems., (© 2023 John Wiley & Sons Ltd.)

Many bacterial pathogens impact the US catfish industry, and disease control can be challenging for producers. Columnaris disease in channel catfish, Ictalurus punctatus, is primarily caused by Flavobacterium covae (formerly F. columnare). Immunostimulants may enhance nonspecific immune responses and offer an alternative to antibiotic treatments in catfish. Furthermore, dietary protein sources and inclusions are also essential to fish health and nutrition and may enhance overall fish performance in pond culture. The current project evaluated two immunostimulants: a protease complex (PC) and a humic substance (HS) derived from a reed-sedge peat product. A 60-day trial examined the effects of five diets on growth performance, immune response and resistance to experimental F. covae infection in channel catfish. Diets included a high-quality fishmeal diet (32%; CF32), a high-protein soy-based diet (32%; C32), a low-protein soy-based diet (28%; C28; predominately used in industry), a low-protein soy diet supplemented with C28 + PC at 175 g metric ton -1 and C28 + HS in a low-protein diet at 23 g metric ton -1 . Following feeding for 60 d, juvenile channel catfish were sampled for growth performance and baseline health indicators (n = 3; body mucus, blood for sera, kidney and spleen). A subset of fish was then subjected to an immersion-based in vivo challenge trial with F. covae (ALG-00-530; 10 6  CFU mL -1 exposure). At 60d post-initiation, there were no dietary differences in the relative growth rate (p = .063) or thermal growth coefficient (p = .055), but the 32% diets generally appeared to perform best. Post-challenge, the C32 group's mortality was higher than the C28 + PC (p = .006) and C28 + HS diets (p = .005). Although not significant, the C28 and CF32 groups also demonstrated higher mortality compared to both PC and HS diets. Sera lysozyme concentration was found to increase following pathogen challenge (p < .001) and in comparison with mock-challenged catfish (p < .001). Elevated expression levels of proinflammatory cytokines (il-1β, il-8, tnf-α and tgf-β) were observed at trial midpoint and post-infection when compared to 60d. The C28 treatment was found to have lower tnf-α expression than the C28 + PC (p = .042) and C28 + HS (p = .042) groups following exposure to F. covae. These challenge data suggest that the immunostimulants (PC and HS) in plant-based protein may be beneficial in protecting against F. covae when offered in low-protein channel catfish diets., (© 2023 John Wiley & Sons Ltd.)

Background: Elemental profiling is a tool that has been proposed to improve the traceability of seafood products. Small sources of variation can affect the outcome of elemental profiling and therefore pose to lower the overall accuracy of analyses. Here, we investigate two potential sources of variation through three experiments: laboratory variation (intra-, interlaboratory variation, and tissue matrix) and tissue variation., Methods and Results: Samples of whitleleg shrimp (Litopenaeus vannamei) were obtained from 20 farms in Ecuador and two farms in Alabama to be analyzed. In the first experiment of the study, samples from Ecuador were analyzed at three different laboratories and compared. Two out of the five elements reported were statistically different across the three laboratories (Cu and Se). In the second experiment, the effect of tissue matrix (ground vs whole tissue during acid digestion) was investigated. Altogether, five out of 29 elements analyzed were statistically different. In the third experiment, samples from two farms in Alabama were analyzed to understand the variation in element concentrations in different tissues (head on shell on (HOSO), headless shell on (HLSO), headless peeled (PLD) and headless peeled and deveined (PLDV)). Elemental concentrations varied across tissues, and patterns in elemental concentrations were site specific. The samples from the two farms were analyzed with a Random Forest classification model to site x tissue groupings with 94% accuracy., Conclusion: The result of this study highlights the following: 1. Consistency in laboratory analysis important in studies that involve element concentrations, as minor differences in methodology can propagate as significant differences in results. 2. In shrimp, elements are compartmentalized in different tissues and elemental profiling should consistently use the same type of tissue., (Copyright © 2022 Elsevier GmbH. All rights reserved.)

Three trials were conducted to evaluate the performances of red snapper, Lutjanus campechanus, in low salinities. The median lethal concentration (96 h LC50) of salinity was determined by trimmed Spearman-Karber method using survival data of fish (18.9 ± 0.2 g) collected after 96 h from acclimation to 2, 4, 8, and 32 ppt salinities in 800 L tanks (n = 3), while the serum osmolality of fish (74.1 ± 3.9 g) was determined after 48 h from acclimation to 6, 8, 16, 24, and 32 ppt salinities in 150 L tanks (n = 3). The growth trial was conducted for 6 weeks in 800 L tanks to determine the growth and survival of fish (18.8 ± 0.2 g) at 8 ppt salinity compared to the control (32 ppt salinity). At the conclusion, the isosmotic point of fish was estimated as 357.2 mmol/kg (correspond to 11.0 ppt salinity), while the 96 h LC50 was estimated as 5.65 ppt salinity. No significant differences were noted for survival and FCR of fish reared in 8 and 32 ppt salinities. However, growth was significantly lower in fish reared in 8 ppt salinity compared to the fish reared in 32 ppt salinity. The reduced growth could be, at least partially, due to the increased osmoregulatory energy expenditure at lower salinities., (© 2021. The Author(s), under exclusive licence to Springer Nature B.V.)

Shrimp are an important and valuable commodity for aquaculture that are widely traded internationally. Widespread antibiotic use has been documented in shrimp farming and is a common source of criticism of aquaculture products. Additionally, previous reports have found some evidence of antibiotic residues in shrimp samples obtained from retail stores in the United States, which is a concern for consumers. To further understand the prevalence of antibiotics in retail shrimp in the United States, shrimp samples obtained from grocery stores across 16 states were analyzed for 74 antibiotic compounds/metabolites at a commercial laboratory. 68 samples were analyzed for a multiclass antibiotic panel which included 66 antibiotics while a subset of 15 samples were analyzed for β-lactam antibiotics, Nitrofurans, and Oxytetracycline. Samples were obtained that were labeled as being from major production countries, including India, Indonesia, Thailand, and Vietnam. No detectable antibiotic residues were found in this survey in any samples. This is contrary to previous findings in frozen shrimp analyzed for antibiotics, which typically report low levels of the prevalence of antibiotics., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2021 The Author(s).)

Shrimp are a globally traded aquaculture commodity that accounts for a large proportion of the monetary value of aquaculture. There are concerns among consumers about seafood labeling fraud and environmental sustainability. Therefore, the geographic origin of shrimp from retail stores was investigated with trace element profiling. 94 shrimp samples were collected from grocery stores across the USA, UK, and EU in 70 different grocery stores. The results of 24 elements are reported. Shrimp samples were from Thailand, India, Vietnam, Indonesia, and Ecuador were shown to have 15 elements that were statistically different across labeled country of origin, with Ecuador having unique post hoc group membership in 5 of the elements. Based on a classification procedure, shrimp were classified to labeled country of origin with an overall accuracy of 71.2%. Overall, the results suggest that elemental profiling could be a traceability tool for classifying samples of shrimp from retail stores., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2021 The Authors.)

This study evaluated the effect of dietary taurine levels on growth, serum biochemical parameters, salinity adaptability, and antioxidant activity of rainbow trout ( Oncorhynchus mykiss ). Four diets were formulated with taurine supplements at 0, 0.5, 1, and 2% w/v (abbreviated as T 0 , T 0.5 , T 1 , and T 2 , respectively). Rainbow trouts (initial weight of 80.09 ± 4.72 g) were stocked in tanks (180 L capacity), and were fed these diets for six weeks and subsequently underwent salinity acclimation. Physiological indicators were determined before salinity acclimation at 1, 4, 7, and 14 days afterwards. Results showed that there were no significant differences in growth performance (final mean weight ranged from 182.35 g to 198.48 g; percent weight gain was between 127.68% and 147.92%) of rainbow trout in freshwater stage, but dietary taurine supplement significantly increased serum-free taurine content. After entering seawater, the Na + -K + -ATPase activity of T 2 group returned to its freshwater levels, and the serum cortisol content was significantly higher than T 0 and T 0.5 groups. At the end of this experiment, the liver superoxide dismutase activity in the T 0 and T 0.5 groups was significantly lower than in the T 1 and T 2 groups, and the liver catalase in the T 0 group was the lowest whereas that in the T 2 group was the highest. Muscle malondialdehyde content was the highest in the T 0 group, and the lowest in the T 2 group. Based on the results of this study, supplement of dietary taurine (0.5-2%) enhanced the salinity tolerance in rainbow trout, which increased with the higher taurine concentration., Competing Interests: Conflicts of interestThe authors declare that there is no conflict of interest., (© Ocean University of China 2021.)

Background: The taxonomic classification of Cannabis genus has been delineated through three main types: sativa (tall and less branched plant with long and narrow leaves), indica (short and highly branched plant with broader leaves) and ruderalis (heirloom type with short stature, less branching and small thick leaves). While still under discussion, particularly whether the genus is polytypic or monotypic, this broad classification reflects putative geographical origins of each group and putative chemotype and pharmacologic effect., Methods: Here we describe a thorough investigation of cannabis accessions using a set of 23 highly informative and polymorphic SNP (Single Nucleotide Polymorphism) markers associated with important traits such as cannabinoid and terpenoid expression as well as fibre and resin production. The assay offers insight into cannabis population structure, phylogenetic relationship, population genetics and correlation to secondary metabolite concentrations. We demonstrate the utility of the assay for rapid, repeatable and cost-efficient genotyping of commercial and industrial cannabis accessions for use in product traceability, breeding programs, regulatory compliance and consumer education., Results: We identified 5 clusters in the sample set, including industrial hemp (K5) and resin hemp, which likely underwent a bottleneck to stabilize cannabidiolic acid (CBDA) accumulation (K2, Type II & III). Tetrahydrocannabinolic acid (THCA) resin (Type I) makes up the other three clusters with terpinolene (K4 - colloquial "sativa" or "Narrow Leaflet Drug" (NLD), myrcene/pinene (K1) and myrcene/limonene/linalool (K3 - colloquial "indica", "Broad Leaflet Drug" (BLD), which also putatively harbour an active version of the cannabichrometic acid Synthase gene (CBCAS)., Conclusion: The final chemical compositions of cannabis products have key traits related to their genetic identities. Our analyses in the context of the NCBI Cannabis sativa Annotation Release 100 allows for hypothesis testing with regards to secondary metabolite production. Genetic markers related to secondary metabolite production will be important in many sectors of the cannabis marketplace. For example, markers related to THC production will be important for adaptable and compliant large-scale seed production under the new US Domestic Hemp Production Program.

The Pacific white shrimp, Litopenaeus vannamei, acclimated to 30 ppt salinity, was transferred to either low (15 and 5 ppt), or high (45 ppt) salinity for 7 days. Hemolymph osmolality, branchial carbonic anhydrase activity, and total ninhydrin-positive substances (TNPS) in abdominal muscle were then measured for each condition. Hemolymph osmotic concentration was regulated slightly below ambient water osmolality in shrimp acclimated to 30 ppt. At 15 and 5 ppt, shrimp were strong hyper-osmotic regulators, maintaining hemolymph osmolality between 200 and 400 mOsm above ambient. Shrimp acclimated to 30 ppt and transferred to 45 ppt salinity were strong hypo-osmotic and hypo-ionic regulators, maintaining hemolymph osmolality over 400 mOsm below ambient. Branchial carbonic anhydrase (CA) activity was low (approximately 100 micromol CO(2) mg protein(-1) min(-1)) and uniform across all 8 gills in shrimp acclimated to 30 ppt, but CA activity increased in all gills after exposure to both low and high salinities. Anterior gills had the largest increases in CA activity, and levels of increase were approximately the same for low and high salinity exposure. Branchial CA induction appears to be functionally important in both hyper- and hypo-osmotic regulations of hemolymph osmotic concentrations. Abdominal muscle TNPS made up between 19 and 38% of the total intracellular osmotic concentration in shrimp acclimated to 5, 15, and 30 ppt. TNPS levels did not change across this salinity range, over which hemolymph osmotic concentrations were tightly regulated. At 45 ppt, hemolymph osmolality increased, and muscle TNPS also increased, presumably to counteract intracellular water loss and restore cell volume. L. vannamei appears to employ mechanisms of both extracellular osmoregulation and intracellular volume regulation as the basis of its euryhalinity.