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The replacement of marine proteins with vegetable proteins or terrestrial animal byproducts in aquaculture diets has been gaining momentum. This study examines the viability of replacing fish meal in shrimp production diets with alternative protein sources (combinations of vegetable proteins) in inland low salinity waters of west Alabama. The test diets were formulated to contain 36% protein and 8% lipid. The basal diet contained 10% fish meal. The fish meal was then replaced (on a weight to weight basis) with poultry meal (PM), pea meal or distiller's dried grain with solubles (DDGS). Two separate experiments (laboratory trial and farm trial) were devised to test the efficacy of the diets for Litopenaeus vannamei reared in low salinity waters. The laboratory trial was conducted at the E. W. Shell Fisheries Research Station in Auburn, Alabama, USA, whereas the farm trial examined the same diets in an outdoor flow-through system at a low salinity shrimp farm in west Alabama. Results indicate no significant differences in shrimp growth, weight gain, survival or feed conversion ratio among dietary treatments, suggesting that PM, pea meal and DDGS can serve as alternatives to fish meal as a protein source for shrimp reared in low salinity environments. [ABSTRACT FROM AUTHOR]

Replacement of fish meal (FM) as a protein source with alternative sources of protein in aquaculture diets has been widely explored in aquaculture. The goal of replacement of FM in production diets is to maintain growth, lower production costs, and increase sustainability. Evaluation of the replacement of FM with poultry by-product meal (PBM) in phase II sunshine bass diets, Morone chrysops × M. saxatilis, was conducted in ponds over 246 d. Four diets were formulated to be isonitrogenous (37%) and isocaloric (4 kcal/g) with different levels of FM replacement with PBM (0, 33, 67, and 100%, Diets 1–4, respectively). Twelve ponds were stocked with 400 phase II sunshine bass (mean weight 5.6 g) and randomly assigned one of the four diets. Fish were fed below satiation based on predicted growth and feed conversion, initially once daily (1700 h) and then twice daily (0700 and 1700 h) as water temperatures and feeding activity increased. Diets were evaluated based on production and performance indicators, body composition, and economic analysis. Production results revealed no significant differences in mean final individual fish weight (511 ± 21 g), net production (4257 ± 247 kg/ha), and survival (85 ± 2%). No significant differences occurred between the performance indicators: mean feed conversion ratio (2.47 ± 0.11), specific growth rate ( 1.84 ± 0.02), and protein conversion efficiency (23 ± 1.3%). Body composition was statistically similar for mean percent fillet weight (49 ± 0.6%) and percent intraperitoneal fat (9.8 ± 1.0%); however, the hepatosomatic index was significantly different between Diets 3 (3.7 ± 0.1%) and 4 (3.2 ± 0.1%). Mean proximate analysis of whole fish (dry weight basis) was not significantly different among treatments yielding the following: percent protein (46 ± 0.4%), lipid (47 ± 1.3%), and ash (8 ± 0.7%). Mean fillet composition (dry weight basis) also revealed no significant differences: percent protein (72 ± 0.8%), percent lipid (30 ± 1.6%), and percent ash (5 ± 0.2%). Proximate analysis was also performed on the diets and revealed a significantly lower protein content in Diet 3 (34.3 ± 0.5%) compared to the other diets (37.1 ± 0.4%). Amino acid analysis of the diets indicated a possible deficiency in methionine in Diets 3 and 4. Based on production, performance, and body composition, the results indicate that complete replacement of FM with PBM in sunshine bass diets is feasible; however, economic analysis suggests that the replacement of FM with PBM may result in reduced revenue over feed costs. [ABSTRACT FROM AUTHOR]

We evaluated the effect of the dietary ratio of digestible energy (DE) : crude protein (CP) on growth performance and nutrient utilization in juvenile Pacific white shrimp Litopenaeus vannamei fed various diets with a constant daily protein input. Juveniles (weight = 0.94 ± 0.04 g [mean ± SE]; n = 30) were stocked in an indoor recirculating-water system (173-L polyethylene tanks; 20 shrimp/tank) and were assigned to four different treatments. Two treatments consisted of 30% and 40% CP diets (30 isoenergetic [ISO]-100% and 40 ISO-75%, respectively) with a constant level of DE (3.28 kcal/g). Two treatments consisted of 30% and 40% CP diets with variable levels of DE (2.70 and 3.6 kcal/g, respectively) that maintained a constant DE:CP ratio of 9 kcal/g of protein (30 ratio [RAT]-100% and 40 RAT-75%, respectively). At the end of the 49-d trial, final weight and weight gain did not differ among the treatments. However, feed conversion ratio (FCR) was significantly lower (P < 0.01) for the 40 RAT-75% and 40 ISO- 75% groups than for the 30 ISO-100% and 30 RAT-100% groups. Final body composition (dry matter, CP, and gross energy) and protein conversion efficiency were not significantly different among the four treatments. However, energy conversion efficiency was significantly higher for the 40 ISO-75% group than for the 30 ISO-100% group. This study demonstrates that when the level of energy is appropriate, increasing dietary protein content allows for reduced feed inputs without affecting shrimp growth performance, while actually improving FCR and water quality due to presumably lower wastage of feed. [ABSTRACT FROM AUTHOR]

This study was designed to determine the production characteristics of the Pacific white shrimp, Litopenaeus vannamei, stocked into grow-out ponds at three different sizes and ages. To meet this goal, three groups of postlarvae (PL) were obtained. The first group was placed in a nursery system for 21 d (N21), the second for 14 d (N14), and the third was stocked directly into ponds (DS). Shrimp from each nursery treatment (three tanks per treatment) were pooled and then subdivided for stocking into four replicate 0.1 ha ponds per treatment, another four ponds were stocked directly (DS) with PL8. All 12 ponds were stocked on the same day at a density of approximately 35 PL/m2, and cultured over a 16-wk period and then drain harvested. After harvest, mean average weights (15.4, 16.9, and 14.9 g), survivals (63, 62, and 64%), FCRs (2.7, 2.5, and 2.7), and average yields (3592, 4005, and 3374 kg/ha) were determined for N21, N14, and DS, respectively. No significant ( P > 0.05) differences were observed among treatments. Regardless of nursing time, nursed juveniles did not differ significantly in production characteristics from shrimp stocked directly from the hatchery. [ABSTRACT FROM AUTHOR]

To allow for the initial identification of practical diet formulations for red snapper culture, the present study was conducted to evaluate the effects of feeding varying levels of dietary protein and lipid on growth and body composition of juvenile and sub-adult red snapper. Twelve diets were formulated to contain varying levels of dietary protein and lipid. In trial 1, juvenile red snapper (initial mean weight 5.9 g) were offered diets with graded levels of dietary protein (32%, 36%, 40%, 44%) and practical energy to protein ratios. In trial 2, juvenile red snapper (initial mean weight 8.64 g) were offered isonitrogenous diets (44% protein) containing graded levels of dietary lipid (8%, 10%, 12%, 14%). Sub-adult fish (initial mean weight 151.5 g) were used in trial 3 and maintained on diets similar to those of trial 1 (32–44% protein). Sub-adult fish (initial mean weight 178.3 g) in trial 4 were offered isonitrogenous diets containing 32% dietary protein and graded levels of dietary lipid (6%, 8%, 10%, 12%). There were no significant differences in growth, feed efficiency ratio (FER) or survival in juvenile fish. Juvenile fish offered 32% dietary protein exhibited a significantly greater (P=0.0497) protein conversion efficiency (PCE) than fish offered a diet containing 44% dietary protein. Juvenile fish in trial 2 also had significantly higher (P=0.005) intraperitoneal fat ratios (IPFRs) at 14% dietary lipid than fish offered diets containing 8–10% dietary lipid, and displayed trends towards greater protein as a percent of whole-body composition at 8–10% dietary lipid. Sub-adult snapper in trials 3 and 4 showed no significant differences in growth, FER or survival. However, in trial 4 there was a general trend towards increased % weight gain (P=0.0615), FER (P=0.0601) and final mean weight (P=0.0596) with increasing levels of dietary lipid. Fish in trial 4 offered 6% dietary lipid also had significantly lower (P=0.0439) IPFR and PCE (P=0.0188) than fish offered 12% dietary lipid. Based on data obtained from these trials, inclusion of dietary protein at levels of 32–36% appears sufficient to support growth. For this level of protein, dietary lipid should be∼10% in order to meet the energetic demands of the fish and to spare dietary protein for growth. [ABSTRACT FROM AUTHOR]

Two experiments were conducted to evaluate phase- feeding strategies on growth and nutrient retention of red drum, Sciaenops ocellatus. The first experiment was conducted over a 17-week period, utilizing sub-adult (initial mean weight, 70.8 g/fish) red drum. Treatments included three fixed-feeding regimes in which the fish were offered diets containing either 44, 40 or 36% protein throughout the growth trial (F44, F40, F36, respectively) and two phased-feeding regimes. The phasedfeeding regimes included feeding the 44% protein diet the first 8 weeks after twhich he fish were switched to the 40 (P44/40) or 36% (P44/36) protein diets. At the conclusion of the experiment, final mean weights ranged from 592.8 to 543.3 g/fish (F44 and F36, respectively). Although statistical differences were not found in final weights (P = 0.1015) of the fish, percent weight gain was significantly reduced as the protein content of the diet was reduced. Similarly, feed efficiency (FE) values decreased as the protein content of the diet was reduced. Although, protein conversion efficiency (PCE) values generally decreased with protein content of the diet there were no statistical differences. The second experiment was initiated with 281 g mean weight fish and was conducted over a 14-week period. Three fixed-feeding regiments (FF44, F40 and F36) and three phased-feeding regimes were evaluated. After six weeks some of the fish (mean weight 448 g) were switched from 44% protein diet to diets containing 40, 36 and 32% protein (P44/40, P44/36, P44/28, respectively). Results of this feeding trial were similar to the first in that performance followed protein intake which in turn paralleled protein content of the diet. In both experiment, considerable differences in final weight were observed but due to variation in the data statistical differences were minimal but the same ranking occurred. Overall, it would appear that fish up to about 450 g will perform best on a 44% protein diet but minimal reduction in growth occur after this point if the protein content of the diet is reduced to as low as 36%. [ABSTRACT FROM PUBLISHER]

The replacement of fish meal with soybean meal in fish diets has met with varying degrees of success. Quite often, poor responses to high soybean meal diets are due to a reduced palatability of the diet when fish meal is removed. Recent work has demonstrated that poultry by- product meal can be used as a substitute for fish meal in practical diets for juvenile red drum, (Sciaenops ocellatus), indicating it may have favorable palatability characteristics for this species. The present research was designed to evaluate the replacement of menhaden fish meal with solvent-extracted soybean meal in practical diets containing 20% poultry by-product meal and formulated to contain 44% protein and 10% lipid. Test diets were adjusted for phosphorus and methionine content to ensure that minimal dietary requirements were maintained. The response of red drum (mean initial weight 179 g) to diets containing fish meal ranging from 40 to 5% of the diet, as well as the response to a low fish meal diet supplemented with krill hydrolysate were evaluated over a 14-week growth period. Final weights (percent gain) ranged from 588 g (237.8%) to 651 g (258.5%) with feed conversion efficiencies ranging from 62.1% to 69.9% and protein conversion efficiencies ranging from 27.8% to 30%. No significant differences (P > 0.05) were observed for diet intake, feed conversion efficiency, protein conversion efficiency, intraperitoneal fat ratio, or weight gain. Significant differences in protein intake and the hepatosomatic index were observed. The present findings suggest that fish meal can be reduced to 5% of the diet by replacing it with solvent-extracted soybean meal as well as methionine and phosphorus supplements. Although diets without poultry by-product meal were not tested, it is presumed that the poultry meal enhanced the palatability of the diets, allowing the replacement of fish meal with soybean meal. [ABSTRACT FROM PUBLISHER]

Two experiments were conducted to evaluate phase- feeding strategies on growth and nutrient retention of red drum, Sciaenops ocellatus. The first experiment was conducted over a 17-week period, utilizing sub-adult (initial mean weight, 70.8 g/fish) red drum. Treatments included three fixed-feeding regimes in which the fish were offered diets containing either 44, 40 or 36% protein throughout the growth trial (F44, F40, F36, respectively) and two phased-feeding regimes. The phasedfeeding regimes included feeding the 44% protein diet the first 8 weeks after twhich he fish were switched to the 40 (P44/40) or 36% (P44/36) protein diets. At the conclusion of the experiment, final mean weights ranged from 592.8 to 543.3 g/fish (F44 and F36, respectively). Although statistical differences were not found in final weights (P = 0.1015) of the fish, percent weight gain was significantly reduced as the protein content of the diet was reduced. Similarly, feed efficiency (FE) values decreased as the protein content of the diet was reduced. Although, protein conversion efficiency (PCE) values generally decreased with protein content of the diet there were no statistical differences. The second experiment was initiated with 281 g mean weight fish and was conducted over a 14-week period. Three fixed-feeding regiments (FF44, F40 and F36) and three phased-feeding regimes were evaluated. After six weeks some of the fish (mean weight 448 g) were switched from 44% protein diet to diets containing 40, 36 and 32% protein (P44/40, P44/36, P44/28, respectively). Results of this feeding trial were similar to the first in that performance followed protein intake which in turn paralleled protein content of the diet. In both experiment, considerable differences in final weight were observed but due to variation in the data statistical differences were minimal but the same ranking occurred. Overall, it would appear that fish up to about 450 g will perform best on a 44% protein diet but minimal reduction in growth occur after this point if the protein content of the diet is reduced to as low as 36%. [ABSTRACT FROM PUBLISHER]

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 use of a co-extruded soybean poultry by-product meal with egg supplement was evaluated as a substitute for fish meal in a practical diet formulated to contain 32% crude protein and 8% lipid. The co-extruded product was substituted for menhaden fish meal on an iso-nitrogenous basis and offered to juvenile Litopenaeus vannamei (mean initial weight±standard deviation, 1.13±0.06 g) over a 6-week period. Inclusion levels ranged from 0% (30 g fish meal/100 g diet) to 100% replacement (0 g fish meal/100 g diet). A fifth diet was formulated to contain no fish meal and 1 g krill meal/100 g diet. Furthermore, a commercial shrimp feed was included in the study to allow for a commercial reference. At the conclusion of the growth trial, survival, final weight, percent weight gain and feed efficiency (FE) were not significantly different among treatments. The inclusion of krill meal did not appear to improve attractability or palatability of the diet. Co-extruded soybean poultry by-product meal with egg supplement appears suitable as a substitute for fish meal in L. vannamei diets. [Copyright &y& Elsevier]

The inland farming of penaeid shrimp in low-salinity waters is now de facto in many regions of the world, yet there is little information pertaining to the suitability of waters with various ionic compositions for shrimp culture. In the present study, short-term (48 h) survival of Pacific white shrimp, Litopenaeus vannamei postlarvae (PL), and long-term (4 weeks) growth and survival of juvenile L. vannamei in various inland saline ground waters were evaluated. A correlation between survival and growth of PLs and the ionic composition of the waters was performed. Short-term bioassays were conducted on 10-, 15- and 20-day-old postlarvae using waters from various wells. Salinity was decreased at a rate of 4 ppt h−1 using fresh water from 24 ppt until a salinity of 2 ppt above the target salinity was reached. Water in the containers was then slowly exchanged with water from inland saline wells. Survival of the PLs was evaluated 48 h after the start of acclimation. In the second study, four replicates of 15 juveniles were placed in 144-l square tanks containing various saline well waters from west Alabama. Growth and survival were evaluated after 4 weeks. The ionic makeup of the various inland well waters from Alabama, Florida, Mississippi and Texas was analyzed to characterize each source. Survival of PL10 shrimp in some of the waters was similar to survival in the low-salinity reconstituted seawater control and was significantly different from the control in other waters. Survival of PL15 was greater than survival of PL10 but similar to PL20. Some waters were unsuitable for shrimp culture at all PL stages tested. Survival and growth of the juveniles paralleled results of the short-term bioassays. Shrimp survived and grew well in waters in which more than 90% of the postlarvae acclimated and survived in. Juvenile survival and growth were intermediate and low in waters in which PL acclimation was intermediate and low, respectively. Survival appears to be positively correlated with ions such as K, Mg and SO4 and negatively correlated with a high concentration of iron. [Copyright &y& Elsevier]

The dietary crude protein requirement of penaeid shrimp is an important nutritional consideration because protein is often the major limiting nutrient for growth. In most cases, research has focused on total dietary protein levels rather than a daily requirement for protein. This research utilized three practical diets containing 16%, 32%, and 48% protein and various daily rations to estimate daily requirements for protein. In the first series of studies, four 28-day feeding trials were conducted to determine the maintenance requirement for protein (protein required to maintain body functions with all other nutrients provided in adequate amounts) by juvenile and subadult shrimp. Shrimp were offered practical diets containing 16% or 32% crude protein. In order to estimate the maintenance requirement, weight gain was regressed against daily protein ration. Juvenile shrimp were found to have maintenance protein requirements in the range of 1.8–3.8 g dietary protein/kg body weight per day (g DP/(kg BWd)), and subadult shrimp were found to have maintenance protein requirements in the range of 1.5–2.1 g DP/(kg BWd). Four additional 28-day feeding trials were conducted to determine the protein requirement for maximum growth by juvenile and subadult shrimp. These studies, utilized three practical diets containing 16%, 32%, and 48% dietary protein. On an isonitrogenous basis, the 16% protein diet produced significantly lower weight gain, feed efficiency (FE), and protein conversion efficiency values, than the 32% protein diet for both the juvenile and subadult shrimp. The 48% protein diet produced significantly lower weight gain in the juvenile shrimp, but there was no significant effect in the subadult shrimp. Feed efficiency values were higher for shrimp fed the 48% protein diet as compared to those offered the 32% protein diet. Broken line analysis was conducted on the growth responses for each diet and each size of shrimp, in order to determine the protein requirement for maximum growth. Protein requirement for maximum growth of juvenile shrimp was found to be 46.4 g DP/(kg BWd) when fed the 32% protein diet and 43.4 g DP/(kg BWd) when fed the 48% protein diet. Subadult shrimp exhibited a maximum protein requirement of 23.5 g DP/(kg BWd) when fed a 32% protein diet and 20.5 g DP/(kg BWd) when fed a 48% protein diet. In summary, FE increased as the protein concentration of the diet increased, and decreased as feeding rates (offered feed/day) increased. Weight gain reflected daily protein intake. Based on these results, a wide range of dietary protein levels could be used to produce maximum weight gain of juvenile and subadult shrimp. Due to a restriction of feed intake and consequently protein intake, low protein diets did not support maximum weight gain. [Copyright &y& Elsevier]

One area with significant potential for improvement in commercial shrimp production is feed management. Consequently, feed management is critical to optimize especially in intensive systems. Hence, the purpose of this study was to observe the response of Litopenaeus vannamei to different feed inputs in an intensive production system. The growth trial was conducted in an outdoor biofloc recirculating aquaculture system consisting of 24, 0.75m2 culture tanks stocked at a density of 160 shrimp/m2 (initial weight 0.17 g) and grown for 63 days. Treatments consisted of seven varying feeding rates (30%, 60%, 90%, 105%, 120%, 135%, and 150%) which was offered 4 times per day, and an eighth treatment that was fed 150% of the standard feeding rate using a belt feeder that fed six times daily. At the conclusion of the trial, significant differences in final weight and feed conversion ratio were observed. Regression analysis performed on the first three feeding rates (30%, 60% and 90%) determined that natural foods were responsible for approximately 280 g of total shrimp biomass, or 17% of maximum biomass gain. Results indicated that increasing feed rates over 100% of the standard rate led to an increase in final weight, albeit shrimp growth shows signs of approaching plateau, and FCR increases. Results demonstrate efficacy of culturing shrimp in high density biofloc systems across a range of feed inputs and achieving desirable growth (1.27–1.55 g/week), final weight (11.62–14.15), feed conversion ratios (1.04–1.19), and survival (94.17–96.94). Restrictive feeding produces the most efficient use of feed, albeit at a cost of total weight gain. As maximum gain is approached, there is an inflection point at 101% of the standard feeding rate where growth and feed utilization decline rapidly leading to increase in FCR and smaller gains in growth. Hence, a goal for maximum gain will be offset by increased FCR. Consequently, to maximize nutrient utilization it is recommended to feed below maximum gain. • Increasing feed inputs led to increased shrimp weight, with lower feed efficiency. • Shrimp can be grown at high densities in biofloc systems and achieve desirable growth. • Restrictive feeding results in the highest feed efficiency. • Natural foods present in the system provided approximately 280 g to shrimp biomass. [ABSTRACT FROM AUTHOR]

Aquaculture production is an important part of the global food supply and has equaled or surpassed fisheries production as the main source of aquatic foods. Aquaculture is a resource intensive practice that can use large amounts of land, water, energy, and cause pollution and degradation to the local environment. Intensive production practices have been criticized in the past for causing environmental harm; however recent studies have suggested that resource use may decrease with increasing production intensities at the farm level. Here we used a conceptual farm to access the impact of a few key production parameters on land, water, and energy use. A series of calculations were conducted at various production intensities with modifications made to the type of feed used and water exchange rate. The resulting relationships were then modeled with production intensity. Additionally, the effect of various feedstuffs on embodied resource coefficients was examined through varying protein and carbohydrate feedstuffs. Land and water use were found to have an asymptotic relationship with production intensity, with the most important factor in land use being production intensity and the most important factor in water use being the water exchange rate. Energy use was found to be higher with a diet that has fish meal as a protein source and at higher water exchange rates. The most land intensive diets used for shrimp contained high fish meal with rice as carbohydrate feedstuffs (0.550 ha/tonne). The most water intensive diet was no fish meal with corn as a carbohydrate (1863 m3/tonne), and the most energy intensive diet was high fish meal with corn as a carbohydrate (11.73 GJ/tonne). The results herein suggest that intensifying shrimp aquaculture could save resources based on per tonne of production basis. [Display omitted] • Intensive shrimp farms save land compared to extensive shrimp farms. • Water exchange is the driving factor with regards to water use at shrimp farms. • Energy use increases, but plateaus with intensification. • There are tradeoffs with different feed ingredients and production systems. [ABSTRACT FROM AUTHOR]

Numerous approaches can be implemented to carry out on-farm Extension demonstrations in aquaculture. The design and approach used are often governed by the problem or question that needs to be addressed as well as budgetary constraints within Extension programs. West Alabama is home to a unique inland marine shrimp industry that uses a low-salinity artesian groundwater source to raise shrimp. Demonstration and technology transfer have been carried out on commercial shrimp farms for nearly 20 years using low-budget on-levee tank systems operated by Extension personnel using this unique water source. On-farm tank demonstrations can be an effective tool for Extension professionals working in aquaculture, especially where unique circumstances exist. [ABSTRACT FROM AUTHOR]

The latest corn‐based ingredient available in the market today is fermented corn protein concentrate (FCPC), which is expected to perform well in shrimp diets due to its nutritional profile and the probiotic properties of the product. The current study was conducted to evaluate the efficacy of FCPC as a replacement for fish meal (FM) in diets of Pacific white shrimps, Litopenaeus vannamei. Graded levels of FCPC (0, 4, 8, 11, 13 and 15 g/100 g) were used to replace fishmeal (16, 12, 8, 4, 2 and 0 g/100 g) in diet, which was evaluated over a 8‐week growth trial (initial weight 0.17 ± 0.01 g; n = 3). At the conclusion, no significant differences were detected in growth, FCR, survival or haematological parameters of shrimp (p > 0.05). Results reveals the efficacy of FCPC to replace 100% fishmeal at an inclusion level as high as 15%, without compromising the performances of shrimp. Significant increase in total haemocyte count (THC) and astaxanthin level in shrimp in response to the inclusion level of FCPC was assumed to be due to the probiotic properties of fermented corn and due to the availability of bio‐convertible carotenoids in FCPC, respectively. [ABSTRACT FROM AUTHOR]

Soybean meal (SBM) from China, Argentina, Brazil, the USA and India was collected to evaluate their performances in the diet of Pacific white shrimp. SBM samples were analysed for proximate composition, amino acid profiles, sugars, fibres, macro and micro minerals. A growth trial was conducted using SBM‐based test diets (350 g kg−1 protein and 80 g kg−1 lipid), and a digestibility trial was carried out from digestibility diets formulated by mixing the basal diet and test ingredients (70:30) on a dry matter basis. Significantly higher growth (as standardized Thermal growth coefficient) was observed in shrimp fed SBM from China over Brazilian SBM. However, growth performances of shrimp fed SBM sourced from USA, Argentina and India were not different to that of Chinese and Brazilian SBM. No significant differences were observed for apparent dry matter, energy and protein digestibility coefficients (<0.05) of SBM among the countries. The differences observed in the ingredient chemical profile of SBM between countries were not reflected in the growth and digestibility data of shrimp. These results highlight the importance of multiple variables influencing the biological value of soybean meals and that simplified generalizations such as country of origin, poorly define the quality of an ingredient. [ABSTRACT FROM AUTHOR]

California yellowtail (CYT), Seriola dorsalis, is a promising candidate for aquaculture due to its rapid growth and high-quality flesh, particularly in markets like Japan, Australia, China, and the United States. Soy protein has shown success as a replacement for marine protein sources in CYT diets, reducing fishmeal levels, though concerns about potential intestinal inflammation persist with the inclusion of solvent-extracted soybean meal. To address this, processing strategies like fractionation, enzymatic treatment, heat treatment, and microbial fermentation have been employed to mitigate the negative impacts of soybean meal on fish nutrition and immune systems. This study focuses on optimizing soybean meal inclusion levels by incorporating advanced soy variants into CYT diets. The eight-week feeding trial, conducted in a recirculation system, featured six diets with sequential inclusion levels (0, 50, 100%) of high protein low oligosaccharide soybean meal (Bright Day, Benson Hill, St Louis, MO) and enzyme-treated soybean meal (HP 300, Hamlet Protein Inc., Findlay, OH), replacing solvent-extracted soybean. The study compares these formulations against a soy-free animal protein-based diet. At the end of the trial, fish were sampled for growth performance, body proximate composition, intestinal morphology, and immune response from gut samples. Results showed consistent FCR (P = 0.775), weight gain (P = 0.242), and high survival rate (99.4 ± 0.5%) among dietary treatments (P>0.05). Histological evaluations revealed no gut inflammation and gene expression analysis demonstrated no significant variations in immune, physiological, and digestive markers apn (P = 0.687), mga (P = 0.397), gpx1 (P = 0.279), atpase (P = 0.590), il1β (P = 0.659). The study concludes that incorporating advanced soybean meal products, replacing up to 20% of fishmeal does not negatively affect CYT's growth and intestinal health. This suggests that all three soy sources, contributing 35% of total protein (15.4 g 100 g-1 diet), can be included in practical diets without compromising CYT's intestinal integrity or growth. These findings have positive implications for the commercial production of CYT and future research on the incorporation of plant-based proteins in aquaculture diets. [ABSTRACT FROM AUTHOR]

The current study evaluates the effect of different Mg levels in low‐salinity (3 g/L) water on growth, survival, haemolymph osmolality, cationic composition in haemolymph, carapace and whole body of Pacific white shrimp, Litopenaeus vannamei. A low‐cost salt mixture (LCSM) comprised of Na, K, Ca and Mg concentrations of 298, 9, 17 and 39 mg/L, respectively, in a 1‐g/L solution was modified by decreasing the Mg level of LCSM to allow different Mg levels in the culture medium (100, 78, 55, 30, 17, 13 and 12 mg/L). Reconstituted sea salt (RSS) was used as the control treatment with Mg level of 129 mg/L. A 42‐day growth trial (initial weight: 0.11 ± 0.01 g and stocking density: 20 shrimp/tank) was carried out in 150‐L plastic tanks, each equipped with a fluidized bed biofilter. As Mg2+ level was reduced, there was a subsequent reduction (p < 0.05) in shrimp performance reflected in final weight, weight gain, haemolymph osmolality, osmoregulatory capacity, Mg2+ concentration in haemolymph, carapace and whole body of shrimp paralleled by an increase in feed conversion ratio (FCR). Low haemolymph osmolality and Mg2+ concentrations (p < 0.05) in shrimp haemolymph were found to be indicative of stress, which was ultimately reflected as reduced growth and increased FCR in low Mg2+ concentrations at 3 g/L salinity. [ABSTRACT FROM AUTHOR]

The suppression of recombination is considered a hallmark of sex chromosome evolution. However, previous research has identified undifferentiated sex chromosomes and sex determination by single SNP in the greater amberjack (Seriola dumerili). We observed the same phenomena in the golden pompano (Trachinotus ovatus) of the same family Carangidae and discovered a different sex-determining SNP within the same gene Hsd17b1. We propose an evolutionary model elucidating the turnover of sex-determining mutations by highlighting the contrasting dynamics between purifying selection, responsible for maintaining W-linked Hsd17b1 , and neutral evolution, which drives Z-linked Hsd17b1. Additionally, sporadic loss-of-function mutations in W-linked Hsd17b1 contribute to the conversion of W chromosomes into Z chromosomes. This model was directly supported by simulations, closely related species, and indirectly by zebrafish mutants. These findings shed new light on the early stages of sex chromosome evolution. [ABSTRACT FROM AUTHOR]

In view of the variability in recommendations for essential amino acid (EAA) and the use of amino acids supplements in shrimp diets, this study was designed to evaluate the efficacy of crystalline amino acids (CAA) in practical shrimp feeds. The basal diet was designed to contain 30% protein and 6% lipid. The primary protein source of the basal diet included: 5% fishmeal, 37% soybean, and 5% gelatin. The intact protein was incrementally reduced to produce diets with 28%, 26%, 24%, and 22% protein. In a second series of diets, CAA were supplemented to the reduced protein diets to return the diets to 30% crude protein. Thus, producing a series of diets containing 30% protein with 2%, 4%, 6%, and 8% crystalline amino acids. The trial was conducted twice to confirm results. Data within treatments for both trials were variable, resulting in limited statistical differences. From a biological standpoint, percentage weight gain (PWG) and mean final weight (MFW) appeared to decrease with intact protein level of the diet (R2 value [PWG], trial 1: 0.30, trial 2: 0.34, R2 value, [MFW] trial 1: 0.44, trial 2: 0.38). None of the diets with supplemented CAA appeared to have reached the same MFW or PWG as the basal diet. Another trial was run using a fishmeal-based diet (30% CP), which in theory should be replete in all essential amino acids, and a soybean meal-based diet at two different protein levels (30% and 35% CP). The soybean meal-based diets were supplemented with essential CAA in one set and only methionine in another to reach the same level as a percent protein, compared to the fishmeal-based diet. No significant differences were observed between the diets in terms of PWG. However, the fishmeal-based diet seemed to outperform most of the other diets in terms of protein retention efficiency. Based on the results of these trials, it is questionable whether CAA are sufficiently utilized by shrimp. [ABSTRACT FROM AUTHOR]

A series of trials were conducted to evaluate the efficacy of a high protein distiller's dried grains (HPDDG) product in practical shrimp feed formulation. In the three growth trials, the basal diet (35% crude protein, 8% lipid) consisted primarily of fish meal (FM), soybean meal (SBM), whole wheat, and corn starch. In trial 1 and trial 2, test diets were produced by supplementing the basal diet with 10, 20, and 30% HPDDG as a replacement for SBM or a combination of FM and SBM, respectively. In trial 1, shrimp (0.18 initial mean weight, 10 shrimp/tank, n = 5) were offered diets for six weeks. No significant differences were detected in the growth and feed conversion ratio (FCR). In trial 2, shrimp (1.24 initial mean weight, 30 shrimp/tank, n = 4) were offered diets over seven weeks. Significant reductions in growth and FCR were observed when shrimp were fed with diets containing > 20% HPDDG. To explore the upper inclusion limit of this product a third trial was conducted for which the basal diet was modified to contain 6, 12, 18, and 24% HPDDG. Shrimp (0.25 initial mean weight, 10 shrimp/tank, n = 4) were offered diets over six weeks. Significant reduced growth and increased FCR as well as enhanced iron and copper contents of whole body were detected in treatment containing 24% HPDDG. Apparent net sulfur, calcium, iron, copper, and zinc retention were also significantly affected by different HPDDG inclusions levels. Apparent digestibility coefficients of energy, protein, and amino acid (AA) for the meal were determined using chromic oxide as an inert marker and the 70:30 replacement technique. Generally, nutrients availability of HPDDG were similar to that of FM, while significantly lower than SBM that were evaluated at the same time. Result of this study indicate that HPDDG is a good plant based ingredient and can be included up to 30% as a replacement of SBM without compromising growth of shrimp. When HPDDG was utilized to replace a combination of SBM and FM, an upper limit of 18% of the diet should be recommended in shrimp feed formulation. The growth depression observed at high levels of inclusion is not likely due to digestibility but a limitation of some nutrients (e.g. marginal amino acids). Palatability shifts or unidentified factors could also be factors influencing the negative effects at high levels (≥ 18% of the diet). [ABSTRACT FROM AUTHOR]

The oxygen demand, acidification potential, and waste loads of carbon dioxide, nitrogen, and phosphorus from feed were determined for production of channel catfish Ictalurus punctatus , tilapia Oreochromis spp., Atlantic salmon Salmo salar , rainbow trout Oncorhynchus mykiss , and whiteleg shrimp Litopenaeus vannamei . Loads of these variables in culture systems (system loads) at typical FCRs ranged from 1090 to 1500 kg t − 1 for feed oxygen demand, 270–440 kg t − 1 for acidification potential, 1186–1885 kg t − 1 for carbon dioxide, 35.9–63.5 kg t − 1 for nitrogen, and 6.1–15.9 kg t − 1 for phosphorus. Using these estimates as representative of feed-based aquaculture and literature data on the proportions of system waste loads typically discharged to the environment (environmental loads), the approximate amounts of waste generated globally by feed-based aquaculture were estimated to be small in comparison to estimates of global anthropogenic waste. Nevertheless, aquaculture should lessen its environmental waste load, and the benefit of improving FCR in reducing waste load was illustrated. Statement of relevance This research will be important in efforts to assess the pollution potential of aquaculture facilities. This will be especially important for aquaculture certification efforts. [ABSTRACT FROM AUTHOR]

Shrimp production has been one of the most important sectors of aquaculture for the last few decades for both its market value and consumer acceptance. The majority of shrimp feeding protocols in typical production setups rely on a combination of feed trays and predetermined feed plans which do not account for real-time consumption or feed preferences. However, for the last decade, the development of passive acoustic monitoring has allowed a much more direct measurement of shrimp feed intake by capturing and integrating clicking sounds produced by shrimp while eating. Integrating acoustic responses with automated feeding systems has allowed the development of on-demand feeding systems for shrimp. Hence, this technology is a potential tool to help understand feed preferences when the feeding protocol is based on real-time demand for feed rather than predetermined quantities. Building on previous research, the goal of this trial was to use passive feedback acoustic feeders as a tool to evaluate if shrimp prefer diets with different protein sources when given the option to eat as much as requested. A 13-week trial was conducted in 16, 0.1-ha outdoor ponds, stocked at 30 shrimp/m2 and equipped with the AQ1 acoustic feeding system. At day 45, the acoustic system was initiated, and four treatments were assigned with a 35% crude protein diet with different protein sources: all-plant, 8% poultry meal (PM), 8% fish meal (FM), and 12% FM. A second growth trial was conducted in 20, 800-L outdoor recirculating system with similar density (30 shrimp/tank), and shrimp were offered a predetermined feeding rate. We did not find statistical differences in any of the main production parameters. Results of this study indicate that shrimp did not clearly favor a particular diet. This suggests that, irrespective of ingredient matrix, a well-balanced feed will produce suitable growth even when shrimp are allowed to determine their feed intake. The use of acoustic feeders opens the door for nutrition research in which the shrimp are fed on demand. [ABSTRACT FROM AUTHOR]

The objectives of this study were to further optimize balance of dietary amino acids (AA) offered to Nile tilapia by investigating the role of dispensable AA (DAA) across the range of indispensable AA (IAA) intakes. The possible limitation of IAA intake in fish consuming diets with high inclusion of crystalline AA (CAA) supplemented to the diets was also confirmed. The basal diet was formulated to contain 22.2% intact protein in which IAA were adjusted to reach 100%, 110% and 120% of NRC requirements with or without DAA supplementation. Glycine and glutamic acid were used as DAA sources at 1:1 and 2:2 ratio to assign 2 levels of DAA at 2% and 4% of the diet. Fish were hand sorted to a uniform size then randomly stocked into 44 aquaria with 15 fish per/tank. Fish were fed 4 times a day to near satiation over a 10-week period. To evaluate feeding regimes on CAA utilization diets with 100% IAA without DAA supplements and 110% IAA with 4% DAA supplements were paired and fed to fish using 2 and 4 feedings per day. Results confirmed that DAA contribute to meeting the nitrogen requirement of fish in which fish fed diets with DAA supplementation had significantly higher growth rates (thermal-unit growth coefficient, TGC) and lower FCR compared to fish fed diets without DAA supplementation. Growth of fish fed diets without DAA supplementation was not comparable to fish fed diets supplemented with DAA irrespective of IAA supplements up to 120% NRC requirement. Fish fed diets with DAA supplements at 4% exhibited superior growth compared to fish fed diets with 0% and 2% DAA supplements. The supplementation of IAA at 110% NRC requirement helped the fish have better growth compared to fish fed diets formulated to 100% NRC. However, no further benefit was observed on growth performance of fish fed diets with IAA supplements up to 120%. Fish fed diets with IAA supplements at 110% NRC and 4% DAA supplements exhibited the best response. The results of this study indicated that although DAA provided benefits in balancing AA profiles of feed, limitation of IAA intake at 100% NRC might cause impaired growth of Nile tilapia. In addition to this, no influence of feeding frequency was obtained on growth performance of fish feed, suggesting that fish can be fed successfully two times per day regardless of high inclusion levels of CAA. • The important role of DAA in meeting the nitrogen requirement of Nile tilapia is confirmed in which DAA inclusion rate of 4% of the diet offering the best performance of fish. • The result of this study also indicates the inferior growth of fish fed diet with IAA supplements at 100% NRC requirements which might result from limitation of daily IAA intake. • Fish can be fed successfully two times per day regardless of high inclusion levels of crystalline amino acid. [ABSTRACT FROM AUTHOR]

Aeration is considered one of the most critical factors in shrimp farming as it affects the metabolism of shrimp and other living organisms within a pond. Maintenance of proper dissolved oxygen (DO) concentrations is critical, as low DO can cause stress, lower resistance to disease, and inhibit growth. Although the effects of single, short-term hypoxia events have been widely studied, little to no research has examined effects of repeated exposure to hypoxia during multiple diurnal cycles that shrimp may experience in aquaculture ponds. Even though the concept is simple, proper DO management is not simple. It is dependent on numerous factors and often based on anecdotal recommendations. The present trial was conducted to help elucidate the effects of DO management strategies on shrimp performance. The trial examined the effects of three different DO set points for automatic aeration on shrimp production and water quality parameters in earthen ponds. In sixteen earthen ponds (0.1 ha), juvenile Pacific white shrimp (⁓0.030 g) were stocked at a density of 25ind/m2. Minimal DO setpoints that activated automatic aeration in each of the treatments were 2.5, 3.5, and 4.5 mg O 2 /L, respectively. Shrimp were fed using the AQ1 passive acoustic monitoring system that was set to not feed while DO was below the threshold of a given treatment. Each of the treatments was applied to 5 ponds, except for treatment 1 (2.5 mg/L) which was applied 6 ponds as it was considered of higher risk. Shrimp growth performance and water quality indicators were monitored weekly. At the end of the 79–81-day trial, results showed that different aeration control treatments had no significant effect in terms of growth performance, feed inputs or productivity parameters. The final weight of the shrimp ranged between 33.3 and 33.6 g, with average final yields of 7500–8500 kg per ha. Nonetheless, mean electrical costs differed significantly between treatments, with higher DO setpoints treatments exhibiting a higher aeration cost with no discernible benefit. Water quality parameters showed no significant difference, except for morning and afternoon DO concentrations. • Required aeration at a given stocking density can be pre-determined by also determining a maximum daily feed amount. • Water column and sediment conditions in a pond need to be well known, to understand the need for aeration in a specific system. • Under optimal culture conditions, the need for aeration can be significantly reduced. [ABSTRACT FROM AUTHOR]

The dinoflagellate Amyloodinium ocellatum is an important pathogenic parasite infecting cultured marine and brackish water fishes worldwide. This includes cultured Florida pompano (Trachinotus carolinus), which is one of the most desirable marine food fish with high economic value in the USA. A. ocellatum infects fish gills and causes tissue damage, increased respiratory rate, reduced appetite, and mortality, especially in closed aquaculture systems. This study mimicked the natural infection of A. ocellatum in cultured pompano and conducted a transcriptomic comparison of gene expression in the gills of control and A. ocellatum infected fish to explore the molecular mechanisms of infection. RNA-seq data revealed 604 differentially expressed genes in the infected fish gills. The immunoglobulin genes (including IgM/T) augmentation and IL1 inflammation suppression were detected after infection. Genes involved in reactive oxygen species mediating parasite killing were also highly induced. However, excessive oxidants have been linked to oxidative tissue damage and apoptosis. Correspondingly, widespread down-regulation of collagen genes and growth factor deprivation indicated impaired tissue repair, and meanwhile the key executor of apoptosis, caspase-3 was highly expressed (25.02-fold) in infected fish. The infection also influenced the respiratory gas sensing and transport genes and established hypoxic conditions in the gill tissue. Additionally, food intake and lipid metabolism were also affected. Our work provides the transcriptome sequencing of Florida pompano and provides key insights into the acute pathogenesis of A. ocellatum. This information can be utilized for designing optimal disease surveillance strategies, future selection for host resistance, and development of novel therapeutic measures. • Transcriptomes of Florida pompano gills after A. ocellatum infection. • IL1 suppression and antibody augmentation were detected in infected fish. • Infection caused oxidative stress, tissue damage and apoptosis in pompano gills. [ABSTRACT FROM AUTHOR]

Abstract: Yellow coloration of catfish fillets has always been a problem. Recently increased consumer scrutiny has brought this to the forefront as a major industry concern. As catfish cannot synthesize xanthophyll, commercial feeds and natural prey items are the initial sources of the yellow color. To better understand the contribution of natural foods, a field study was conducted to identify if there were correlations of yellow fillet and natural productivity under commercial pond conditions. Upon notification from a west Alabama fish processor, yellow catfish fillets and natural organism samples (plankton, shad and snails) were collected from different farm ponds in west Alabama. “Clean” catfish fillets (no unacceptable yellow coloration) and natural organisms were also collected at multiple farms where problematic yellow fillets were not present. In addition to large food items, microorganism samples from the ponds were collected by pumping pond water through two filters (sizes 20μm and 75μm) for a period of 10min. The fillet and field samples were analyzed quantitatively for xanthophyll levels through High-Pressure Liquid Chromatography (HPLC). Results revealed a correlation between xanthophyll level in catfish fillets and in microorganisms (>75μm). Results indicate that natural productivity consumed by gizzard shad and other filter feeders appears to contribute to the xanthophyll levels in catfish fillets. [Copyright &y& Elsevier]

Abstract: The objective of this study was to evaluate the effect of stocking density on the growth performance and economic feasibility for the culture of Litopenaeus vannamei fed plant based diets and cultured in production ponds and an outdoor tank system. Juvenile shrimps (0.015g initial weight) were stocked in sixteen 0.1ha ponds with stocking densities of 17, 26, 35, and 45shrimpm−2 and cultured under standardized pond production conditions for 16weeks. Daily feed rates were predetermined using expected growth per week of 1.3g, a feed conversion ratio (FCR) of 1.2, and an estimated survival rate of 78%. Additionally, juvenile L. vannamei (2.8g initial weight) were stocked into 24,800-L tanks at the densities of 15, 25, 35, 45, 55, and 65shrimpm−2 with 4 replicates per treatment and cultured for 10weeks. Daily feed inputs were calculated based upon an expected weekly weight gain of 1.3g and an expected FCR of 1.2. At the conclusion of the trials, final production, final mean weight, FCR, size distribution and survival were determined. The results for the pond study demonstrated that there was a trend of negative correlation between stocking density and growth. Mean final weight (±SD) of shrimp across treatments ranged from 20.70 to 25.25g. Survival ranged from 58.0 to 65.1%, and FCR was between 1.17 and 1.54. These differences were not significant (P≥0.10) among treatments, however, higher stocking density resulted in significantly greater yield. Final production was between 2660 and 6149kgha−1. There were no significant differences in partial returns among different densities for the pond study. The results for the outdoor tanks showed that shrimp growth were inversely related to stocking density, with mean final weight ranged from 13.42 to 16.13g. Final biomass ranged between 286.15 and 637.20gtank−1. There was a negative correlation between stocking density and FCR with FCR ranging from 1.15 to 1.54. Survival ranged from 93.4±5.6 to 100.0±0.0%, however, there was no significant effect of stocking density on survival rate. Additionally, there were no significant differences in production value and partial income data among treatments under pond production study. [Copyright &y& Elsevier]

Abstract: A 12-wk feeding trial was conducted with juvenile (0.6±0.3g) Pacific white shrimp, Litopenaeus vannamei, to evaluate the need for cholesterol supplements in plant based diets for shrimp reared in an outdoor system in the presence of natural foods. The basal diet was formulated with no fish meal and targeted crude protein levels of 35%. Five levels of supplemented cholesterol (0, 0.02, 0.04, 0.06, and 0.08%) resulted in diets analyzed to contain 0.061, 0.076, 0.110, 0.125, and 0.155% cholesterol. In addition, two levels of phytosterol supplements (0.05, 0.1%) were evaluated. Mean final weights and growth ranged from 19.13 to 20.20g and 1.52 to 1.61g/week, respectively. One-way ANOVA showed a significant difference (P ≤0.05) among shrimp fed diets containing the various levels of cholesterol, with diets containing ≤0.076% total cholesterol producing smaller shrimp. No significant differences were detected among treatments with respect to survival, yields or FCR. Performance did not significantly improve when shrimp were offered diets supplemented with 0.06% (0.125% total cholesterol) or higher levels of cholesterol. This would suggest that the cholesterol requirement for L. vannamei grow-out lies somewhere between 0.076 and 0.11%, however, a regression analysis predicted the cholesterol requirement for maximum growth to be 0.15% of the diet. Performance of shrimp fed the diets with two levels of phytosterol supplementation was compared to those fed the basal diet (no cholesterol supplementation) and the highest level of cholesterol (0.08%) supplementation. Mean final weight and growth rates were significantly different (P ≤0.05) with the mean final weights of the lowest phytosterol inclusion (0.05%) and the 0% cholesterol supplementation being similar, 19.03 and 19.13g, respectively and the highest levels of phytosterol (0.1%) and cholesterol (0.08%) supplementation being similar, 20.18 and 20.20g respectively. Likewise, the growth per week showed a similar trend, with the two lower levels of ingredient inclusion resulting in a growth rate of 1.52g/week and the higher levels achieving a growth rate of 1.61g/week. Survival, yield, and FCR were not significantly different between treatments. [Copyright &y& Elsevier]

Abstract: The present study was carried out to evaluate the effect of dietary lipid levels on growth performance and body composition of juvenile marbled spinefoot (Siganus rivulatus). Six iso-nitrogenous (301.0gkg−1 crude protein) and iso-energetic diets (16.0MJ gross energykg−1) were formulated to contain 25, 45, 65, 85, 105, and 125g lipidkg−1. Twenty juvenile fish (2.9g±0.01; mean±SE) were randomly assigned to triplicate treatments and offered the test diets three times daily to apparent satiation for 7weeks. Survival was greater than 95% in all treatments. Fish offered the diet with the lowest lipid content (25gkg−1) exhibited lowest growth performance. No significant differences in growth performance were detected among all other treatments. However, analysis of final body weight by second order polynomial regression suggested that the dietary lipid requirement for optimal growth in juvenile marbled spinefoot is 98gkg−1.There were no significant differences in condition indices (K), fillet yield and hepatosomatic index (HSI) values among treatments. Viscerosomatic index (VSI) (13.35%±0.42) of fish offered the diet with 125gkg−1 lipid was significantly greater than the VSI (10.00%±0.35) of fish offered the diet with 25gkg−1 lipid. A trend of increasing VSI with an increase in dietary lipid was obvious. Increasing dietary lipid levels beyond 85gkg−1 resulted in increase in whole body lipid content. No significant differences in moisture content (69.3–71.6%), protein content (13.1–14.6%), and ash content (2.8–3.2%) were observed among treatments. Based on our results, marbled spinefoot rabbitfish have low dietary lipid requirements and increasing dietary lipids increased the lipid proportion of body weight significantly. [Copyright &y& Elsevier]

Abstract: Due to economic pressures from high fish oil prices and from buyers and consumers requiring sustainable practices, the use of high levels of fish oils in aquafeeds is no longer desirable. The present study evaluated the replacement of marine fish oil (MFO) with alternative oils in a plant based diet. Litopenaeus vannamei juveniles (1.55g) were stocked into 650L circular tanks at 26shrimptank−1 and fed 13 experimental diets over a 58-day growth trial. Diets were formulated with soybean oil (SO) as replacement for MFO at inclusion ratios of 100:0, 50:50, 40:60, 30:70, 20:80, and 10:90 as MFO:SO. The next series of diets were formulated to keep n-3/n-6 ratios close to the ratio attained at 50% MFO replacement while removing MFO, this was done by increasing linolenic acid content through the use of linseed oil (LO), resulting in the following MFO:SO:LO ratios, 40:53.4:6.6, 30:56.9:13.1, 20:60:20, and 10:63.7:26.3. Three additional diets were evaluated which included a high LO (10:90 as MFO:LO) and a high soybean oil diet using a low linolenic acid acid soybean oil (LLSO) at a 10:90 ratio of MFO:LLSO. The final diet was a commercial diet which served as a reference. The results showed no statistically significant differences in final mean weight, growth, survival or FCR values of shrimp fed the various diets. Fatty acid (FA) profiles of tail muscle form shrimp fed the various lipid sources in general conformed to the lipids of the feed. Shrimp fed Diet 11, with 19.81mg of linolenic acid per gram of diet had the highest amount of this FA in shrimp tail muscle (5.61mgg−1 wet tissue) and a relatively high n-3/n-6 ratio of 1.15, but at the same time, practically the lowest content of eicosapentaenoic (4.07mgg−1 wet tissue) and docosahexaenoic (2.04mgg−1 wet tissue) acid among the dietary treatments. This response is typical for animals that cannot elongate and desaturate poly-unsaturated into highly-unsaturated FA (HUFA). As shrimp production was not influenced by lipid source or n-3/n-6 ratio, clearly a range of lipids could be used to support growth. However, as the optimal dietary approach for humans is to consume preformed n-3 HUFA by eating seafood, it would be best for farmed shrimp to retain high levels of n-3 HUFA and high n-3/n-6 ratios as found in wild caught shrimp. [Copyright &y& Elsevier]

In this study, we aimed to investigate the inclusion effect of hydrolyzed salmon meal (HSM) in combination with enzyme-treated soybean meal (ESBM) with or without pH adjustment to completely replace dietary FM on the growth, body composition, and the distal intestine condition of the fish. For that purpose, four experimental diets were formulated to be iso-nitrogenous and iso-lipidic and to contain 400 g kg−1 crude protein and 80 g kg−1 lipid. A reference diet contained 150 g kg−1 FM, 450 g kg−1 soybean meal (SBM), and 39.5 g kg−1 ESBM, and the second diet was formulated replacing FM with 190.6 g kg−1 ESBM. The third diet was produced by supplementing 40 g kg−1 hydrolyzed salmon meal (4% HSM) into the diet formulation at the expense of ESBM, and the fourth diet was produced similar with the third diet, but the pH of the diet was adjusted to match the value in the reference diet (4% HSMA). All test diets were supplemented with taurine at the level of 5 g kg−1. Diets were fed to apparent satiation to triplicate groups of Florida pompano juveniles (mean weight 11.88 ± 0.18 g). After 8 weeks of growth, there were no significant differences in the final weight, percentage weight gain, thermal growth coefficient, feed intake, survival rate, and feed conversion ratio in fish offered the various diets. Nor were significant differences observed in the dry matter composition of the fish in all treatments and only minor changes in the histomorphological of distal intestine as the FM was replaced by plant ingredients. Overall, the adjustment of pH level of the diet containing 4% HSMA did not have any significant effect on the growth and physiological function of fish compared to the group of fish fed with diet without pH adjustment. [ABSTRACT FROM AUTHOR]

This study aimed to compare the growth performance, food consumption, and acoustic feeding behavior of two size classes of Litopenaeus vannamei fed on extruded and pelleted diets. Two similar diets (35% crude protein) prepared by extrusion or pelletizing methods were offered to two shrimp size classes: small (3.83 ± 0.16 g) and large (10.28 ± 0.37 g). Shrimp were reared in 100-L aquaria (salinity 6 ppt, temperature 28 °C); growth performance and survival were analyzed at the end of 4 and 8 weeks for small and large size classes, respectively. Hydrophones recorded the sounds of shrimp feeding activity for 30-min intervals, after food remains were collected to evaluate consumption. Physical (pellet durability index, hardness, water absorption, density, sinking velocity, dry matter retention) and chemical (aromatic amino acids (AAA) leaching) characteristics of the diets were evaluated before and after soaking. Extruded diet presented higher durability and hardness before soaking, but its higher water absorption resulted in markedly texture softened and higher AAA leaching. Both shrimp size classes presented no significant differences in final mean weight, biomass, weight gain, survival, food conversion, and food consumption between pelleted or extruded diets. The mean acoustic energy did not differ between diets, but larger shrimp produced higher energy during feeding activity. The energy showed a significant progressive decrease along time intervals (10, 20, and 30 min) for both size classes and diets. Despite the different characteristics between pelleted and extruded diets, both resulted in similar shrimp performance and acoustic feeding profile activity under laboratory conditions. [ABSTRACT FROM AUTHOR]

• The study was conducted to evaluate the performance of Nile tilapia fed graded levels of protein with or without IAA supplemented in practical diet. • Ideal protein concept can be applied in formulating the diets for Nile tilapia to optimize AA profile of the diets. • Well-balanced IAA profile can be used to reduce the intact protein levels of feed (32 to 27.2 %) without causing impaired growth of fish. The study was conducted to evaluate the production performance of Nile tilapia Oreochromis niloticus fed graded levels of protein with or without indispensable AA (IAA) supplemented in practical diets. A control diet containing 32 % intact protein was modified to meet the respective requirements of IAA based upon NRC recommendations for Nile tilapia. From this diet, two series of diets were formulated to confirm the efficacy of crystalline AA (CAA) used as supplements in the practical diets of fish by applying "ideal protein concept". In the first series of diets, intact protein was reduced gradually from 32 to 24 % of the diet without IAA supplementation. In the second series of diets, the same dietary protein levels were formulated; however, the IAA profiles of these diets were modified to meet the respective requirement of Nile tilapia (NRC, 2011). Five commercially-available AAs, including methionine, lysine, tryptophan, histidine and valine, were supplemented if necessary to attain the targeted AA profile. The supplementation of all deficient IAAs was obtained in the last diet to evaluate if there is further benefit of using IAAs other than commercial AAs to balance the AA profiles of diets. Four groups of Nile tilapia (12.7 ± 0.2 g) were fed each diet four times daily to near satiation. The results obtained after eight weeks indicated that fish fed diets with IAA supplementation had significantly higher weight gain compared to fish fed diets without IAA supplementation. Fish fed intact protein levels above 27.2 % with the supplementation of IAA up to the reported requirement (NRC, 2011) showed comparable performance to fish fed the control diet. The reduction of intact protein further than that, however, resulted in reduced growth rate (thermal-unit growth coefficient) of fish even though the IAA profiles of these diets met the reported requirement of tilapia for optimal growth (NRC, 2011). Based on the data obtained from this study, it can be concluded that ideal protein concept can be applied in formulating the diets for Nile tilapia to optimize AA profile of the diets. Well-balanced IAA profile can be used to reduce the intact protein levels of feed (32 to 27.2 %) without causing impaired growth of fish. [ABSTRACT FROM AUTHOR]

Land-based seaweed ponds can produce 500–700 t of fresh weight (FW) ha−1 year−1, but their profitability can be cut by the cost of pond construction, including ground leveling, infrastructure cost, and water agitation. A potentially cost-effective, land-based seaweed culture approach where seaweed grow on substrates by spray culture has been examined. We measured the yield and biomass quality of three intertidal cultivable seaweeds, Ulva fasciata, Ulva compressa, and Hypnea musciformis, in spray (known elsewhere also as film or drip culture) and pond culture approaches, varying surface inclination and nutrient loading. These technical details are necessary for the evaluation of the approach and for upscaling. The best yield (up to 84 g FW m−2 day−1, 44–84% of yield in ponds) and quality (protein content and additional parameters) of spray-grown U. fasciata was obtained on 6°-inclined trays with highly fertilized water. The highest protein content (24.5%), but with reduced yield, was obtained on 80°-inclined trays. H. musciformis and U. compressa, apparently thanks to their stringy morphologies, yielded in spray culture up to 286 g FW m−2 day−1 and 172 g FW m−2 day−1, respectively. The overall quality and resilience of spray-grown algae profited from nutrient enrichment, and the best yields were achieved with enrichment of 10 g N and 1 g P m−2 day−1 in H. musciformis and 15 g N and 1.5 g P m−2 day−1 in both Ulva species. Biomass growth occurred in layers, which visibly differed in color and consistency. A thin bleached top thalli layer protected the biomass below from dehydration and bleaching and allowed there a high photosynthetic rate. A spray culture of Ulva sp. on seawater-sprayed cement tiles, with minimal maintenance, yielded up to 50 g FW m−2 of tile day−1. Economically, spray culture appears to be particularly suitable to the stringy algae. [ABSTRACT FROM AUTHOR]

This study was conducted to evaluate the effect of dietary eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) levels on the fatty acid composition, salinity tolerance and antioxidant status of rainbow trout (Oncorhynchus mykiss). Four diets were formulated with total EPA and DHA contents of 5.41, 9.55, 13.97 and 17.88 g/kg (abbreviated as ED‐5.41, ED‐9.55, ED‐13.97 and ED‐17.88 respectively). Rainbow trout (initial weight of 90.61 ± 9.25 g) were fed the experimental diets for 8 weeks to accumulate significant differences in fatty acid composition and subsequently underwent salinity acclimation. Our results indicated that high dietary EPA and DHA significantly improved the EPA and DHA content in fish tissues. The serum osmolality of fish returned to their freshwater values in the ED‐9.55, ED‐13.97 and ED‐17.88 groups. The Na+, K+‐ATPase (NKA) activity of fish in the ED‐13.97 group changed dramatically to adapt the fish to the hypertonic environment. Moreover, there was no significant difference in the serum cortisol concentration and liver catalase (CAT) activity of fish in the ED‐13.97 group during salinity acclimation. The liver superoxide dismutase (SOD) activity in the ED‐13.97 group was significantly higher than that in ED‐5.41 and ED‐9.55 groups at the end of salinity acclimation. The muscle malondialdehyde (MDA) content in the ED‐13.97 group was significantly lower than that in the ED‐17.88 group before salinity acclimation and significantly lower than the ED‐5.41 and ED‐17.88 groups on day 7 of acclimation. The results of this study indicate that the rainbow trout in the ED‐13.97 group exhibited optimal salinity acclimation performance. [ABSTRACT FROM AUTHOR]

A series of trials were conducted with Pacific white shrimp Litopenaeus vannamei, to evaluate the efficiency of two salmon meals as compared to anchovy meal. The basal diet contained 200 g/kg anchovy meal, which was systematically replaced (0%, 50%, 75% and 100%) with salmon meal on an isonitrogenous basis. Another two diets were formulated with a hydrolysed salmon meal to replace 50% and 100% anchovy meal. Each diet was randomly fed to four replicate groups of 25 and 30 shrimp per tank in clear (indoor) and green (outdoor) water trials, respectively. The results showed that growth performance and feed conversion ratio were not statistically different when salmon meal replaced anchovy meal in both trials. However, when hydrolysed salmon meal was used to replace 100% of the anchovy meal, growth performance of the shrimp significantly decreased. The four kinds of fish meal (anchovy, salmon by‐product meals and menhaden) were evaluated in an ingredient digestibility trial using the 70:30 replacement technique. In general, dry matter, energy, protein and individual amino acids digestibility of salmon meal were significantly higher than those of menhaden and anchovy meal. Results of this study demonstrated that salmon meals are a good protein sources which can replace anchovy meal. [ABSTRACT FROM AUTHOR]

Pacific whiteleg shrimp is the topmost aquacultured species produced in the world. However, shrimp feeding behavior results in unnecessary expenditures, as some of the feed offered is not entirely consumed. Nowadays, aquaculture has become more accepting of using animal by-products such as poultry meal as a protein source to replace fishmeal. Unfortunately, such by-products might affect shrimp acceptance of the offered feed. The present work evaluates the use of a chemosensory feed effector with attractive properties on the feeding behavior, growth performance, and salinity stress tolerance in juvenile Litopenaeus vannamei. Nine diets were formulated to contain either poultry meal (6%), or fishmeal (6% or 12%) as animal protein source, with feed effector supplemented at 0, 0.1, and 0.2%. The various diets were offered to naïve and non-naïve shrimp to evaluate feed consumption. Concurrently, shrimp feeding behavior was monitored using passive acoustic monitoring. Afterwards, a 42-days growth trial was performed followed by a salinity stress trial were performed to evaluate the effect of the feed effector in shrimp diets on animal growth, survival, and stress tolerance. Results of the present study indicate significant positive relationships between the number of clicks and feed consumed after 30 min (p < 0.001, r = 0.46 to 0.69). Additionally, shrimp offered the poultry meal-based diets produced significantly more "clicks" when the diets were supplemented with the feed effector, compared with the rest of the diets. However, the shrimp consumed poultry meal-based diets similarly to the fishmeal-based diets, only when supplemented with the feed effector. Interestingly, no significant differences were observed in terms of final biomass, final average individual weight, weight gain, FCR, or survival. However, salinity stress trial results indicate significantly better survival when offered diets supplemented with the feed effector, regardless of the level of inclusion. Results of the present work suggest that supplementing the feed effector to shrimp diets improves palatability and shrimp acceptance of diets formulated with poultry meal as sole animal protein source, as well as improves shrimp tolerance to salinity fluctuations. In an era of limited resources, supplementation of poultry meal-based shrimp diets with feed effector improves overall profitability by obtaining good shrimp growth with less expensive diets, and despite of stressors. • Feed effectors can improve shrimp acceptance to feed formulated with animal by-products proteins to replace fishmeal. • Passive acoustic monitoring is useful to assess shrimp feeding on animal by-products based feed, with feed effectors added. • Feed effectors have the potential to improve shrimp tolerance to salinity stress. • The feed effector positively influenced the number of clicks emitted by the shrimp when feeding. • Despite not influencing growth or survival, shrimp tolerance to salinity stress improved with feed effector addition. [ABSTRACT FROM AUTHOR]

Abstract This study examined the effects of replacing fish meal (FM) with three different types of soybean meal (SM) including untreated SM, Bacillus pumillus SE5 (BP) fermented SM (BPFSM) and Pseudozyma aphidis ZR1 (PA) fermented SM (PAFSM) in diets for Japanese seabass (Lateolabrax japonicus). A basal diet was formulated using FM (FM diet), and six other diets were produced by substituting 40 or 80% of FM with SM, BPFSM or PAFSM (SM40, SM80, BPFSM40, BPFSM80, PAFSM40 and PAFSM80 diets). Each diet was fed to triplicate groups of fish (7.14 ± 0.05 g) twice daily for eight weeks. Replacing 40% of FM with SM sources did not significantly influence growth (P > 0.05), while increasing the substitution level to 80% led to reduced growth rates (P < 0.05). The groups received SM80 and PAFSM80 diets showed significantly higher feed conversion ratio and lower protein digestibility than FM group. Furthermore, notably lower dry matter digestibility was detected in SM80 group. Remarkably lower serum total antioxidant capacity was found in the SM80 group, and catalase activity did not significantly differ between FM and BPFSM40 groups. Serum malondialdehyde concentration was enhanced by increasing FM replacement level and the highest value was observed in the SM80 fed fish. FM and PAFSM40 groups showed significantly higher lysozyme activity than the SM80 group. Fish fed the BPFSM40 diet exhibited the highest complement C3 activity and the lowest value was observed in the SM80 group. Expression of lysozyme gene in spleen was down-regulated in the SM80 group, and no significant difference in expression of C3 gene was found among FM, BPFSM40 and PAFSM40 groups. Digestive enzymes activity and gut morphology were significantly influenced by FM replacement. Expression of HSP70 and pro-inflammatory genes including TNF-α and IL-1β were up-regulated by FM replacement and relatively lower expression levels were found by using fermented SM. An opposite trend was observed for the anti-inflammatory TGF-β gene expression. Serum d -lactate concentration was significantly increased by replacing 80% of FM with any of the SM sources. These findings indicated that using fermented SM, particularly BPFSM, beneficially influences feed utilization, antioxidant capacity, innate immunity and gut health in juvenile Japanese seabass. Highlights • Yeast and bacterial fermented soybean meal were tested in Japanese seabass feed. • Fermentation with Bacillus pumillus SE5 improved digestibility of soybean meal. • Fermented soybean meal enhanced antioxidant capacity and innate immune response. • Fish meal replacement with soybean meal suppressed digestive enzymes activity. • Fermentation of soybean meal ameliorated the damaging effects on gut structure. [ABSTRACT FROM AUTHOR]

Chicken feather meal is often viewed as an undesirable product, as most people think of ground up feathers, which have many processing and nutritional issues. However, modern feather meals are produced through a hydrolysis process which greatly improves protein digestibility. Given the poor understanding of the quality of these meals, we chose to evaluate the efficacy of hydrolyzed feather meal (HFM) as a protein source in channel catfish feeds. For this work, we investigated the replacement of either poultry-by-product meal (PBM) or soybean meal (SBM) in a practical feed formulation for juvenile catfish. The basal diet contained 6% PBM and 56.5% SBM. For the first series of diets, we incrementally replaced PBM with 2.5% and 5% hydrolyzed feather meal (HFM). The second series included five experimental diets with SBM replaced by HFM at a rate of 2.5%, 5%, 7.5%, 10%, and 15%. Diets were formulated to be iso‑nitrogenous and essential amino acids were supplemented to maintain minimal levels that met the nutritional requirements. Catfish were stocked at 15 fish per aquaria using four replicates per treatment and grown for 78 days. The survival of the catfish was above 85% across all treatments with no significant differences found due to diet. Apart from one diet, the inclusion of HFM did not influence the growth or FCR of the fish. Diet 3, which contained 5% HFM as a complete replacement for PBM had significantly lower growth and FCR than the other treatments. These results indicate that up to 20% HFM can be used in catfish feeds a as long as there is a low level of another animal protein. However, the complete replacement of PM with HFM was not successful. • HFM can successfully SBM at rates up to 15% without compromising fish growth performance. • Apart from one diet, the inclusion of HFM did not influence the growth or FCR of the fish. • Up to 20% HFM can be used in catfish feeds a as long as there is a low level of another animal protein. • Complete replacement of PM with HFM was not successful. [ABSTRACT FROM AUTHOR]

Feed is one of the primary costs associated with commercial production of Pacific white shrimp (Litopenaeus vannamei). This high cost is the combined outcome of feed cost and feed management. As feeding technology evolves, specifically the use of automated feeding systems, it is vital to reevaluate the optimal protein levels in diets for the best production outcomes. The use of passive acoustic monitoring (PAM) adds another level of complexity to how shrimp respond to feed because it has the potential to automatically adjust feed offerings based on protein because of the shrimp's response. In this research, four diets with various protein levels (40, 35, 30, and 25%) were fed to shrimp which were stocked (0.045 g, 25 shrimp/m2) into 16 ponds (0.1 ha) and cultured for an 85-day production cycle. Shrimp were fed on demand using an automatic feeding system with passive acoustic feedback. Final individual weights were significantly smaller for shrimp fed the 25% diet (31.22 g) compared to all other diets. The total biomass of all ponds ranged from 6928 to 7878 kg/ha for shrimp offered the 25%- 40% diets, respectively. Other than final weight, analysis of total biomass and all other production data showed no differences between treatments (p > 0.05). Whole-body analysis revealed significant differences in fat (p = 0.0002), copper (p = 0.018), and apparent net protein retention (p = 0.0025). Analysis of economic values indicated a statistically significant difference between treatments for feed cost (p = 0.020). The significantly lower individual weights from shrimp fed the 25% diet and the notably lower total biomass resulted in a subsequent difference in class size distribution. This ultimately led to a difference in the market value of shrimp ranging from $60,383 to $71,247. Although the 40% protein diet was significantly higher in cost it showed no differences in production or economic outcomes and higher level of water born TAN as compared to the other diets. Overall, these results indicate that a 30–35% protein diet would be the most efficient for use in pond production of Pacific white shrimp under the culture conditions examined in this study. • Dietary protein levels in shrimp diets should be reevaluated as feed management technology evolves • Passive acoustic monitoring feed technology could automatically adjust with dietary protein level based on shrimp response • Shrimp and/or passive acoustic monitoring feeding systems did not respond differently to variable levels of dietary protein • Lower protein input resulted in smaller individual weights of shrimp • Higher protein input led to increased total ammonia nitrogen levels [ABSTRACT FROM AUTHOR]