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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]

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]

Substitution of fish meal (FM) as a protein source in aquaculture diets is required to reduce cost and promote a sustainable industry. Potential protein sources include a range of traditional products from agricultural production such as plant or animal proteins. However, there are also a number of manufacturing coproducts, including bacterial dried fermented biomass (DFB,) for which there is an increased interest. Hence, the objective of this study was to evaluate DFB as a replacement for FM in practical diets for Florida pompano,Trachinotus carolinus. Four diets were prepared in which different levels of FM (15%, 10%, 5%, and 0% of the diet) were replaced with DFB (0%, 4.27%, 8.54%, and 12.82%) on an iso-nitrogenous and iso-lipidic basis, to contain 40% crude protein and 10% lipid. A 10-week growth trial was conducted in a recirculating system consisting of 12 indoor 1.0 m3tanks, stocked with 20 juvenile pompano (mean initial weight 8.1 g) per tank. There were no significant differences in final weight (64.5 g−79.5 g), survival (81.7%–96.7%), percent weight gain (711.6%–879.0%), FCR (2.1–2.0), or thermal-unit growth coefficient (0.1013−0.1149), regardless of the levels of dietary FM or DFB tested. Based on these results, it is recommended that DFB can be included up to 12.8% in practical diets for Florida pompano without significantly reducing growth performance. The response to higher levels of DFB inclusion should be evaluated. [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 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 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]