Wiles N. Brandon, Gregory A. Dudenhoeffer, and Thomas R. Omara-Alwala
Crappie (Pomoxis spp.) is a popular sport fish with food fish potential. Feeding behavioral patterns should be considered prior to nutrtitional studies. The objective of this study was to determine the best feeding time and duration for hybrid crappie raised in indoor recirculating aquaculture systems. Three feeding treatments with three replciates consisted of two 12 hour feeding periods initiated at 0800 (12h-amLD) and 1700 (12h-pmLD) and a 24 feeding period started at 0800 (24h-amLD). Treatments in experimental tanks were arranged in a random block design and stocked with 14 hybrid fingerlings fed for 12 weeks. Fingerling fish were spwaned in pongs using previously feed trained black crappe females (P. nigromaculatus) and white crappie males (P. annularis). Weight gain, feed conversion ratio (FCR), survival rate, consumption rate and proximate analysis of fish flesh and visceral were measured. Mean mass weight gains for 12h-amLD, 12h-pmLD, and 24-amLD were 153, 196, and 139g. There were no significant differences (p ≥ 0.05) among weight gains. Mean FCR were 1.69, 1.82, and 2.57 for 12h-amLD, 12h-pmLD, and 24-amLD, respectively. A significant diffference in FCR occured between 24h and the two 12 hour treaments. There were no significant differences in survival rate, feed consumption, or composition of fish flesh among treatments. The only significant difference in visceral was between 12h treatments for ash. This study indicated that feeding times or durations did not affect hybrid crappies body weight gain. However, there could be a FCR advantage with the 12 hour feeding schedules.
Wiles N. Brandon, Gregory A. Dudenhoeffer, Yongfang Zhang, and Thomas R. Omara-Alwala
This study evaluated growth rates of juvenile bluegill (Lepomis macrochius) fed different protein levels, raised indoors. Six experimental diets containing protein levels of 32, 35, 38, 41, 44, and 47% with 346 kcal/g energy were fed to four replicates of 12 fish with initial mean weight of 24.9±0.51g. Fish were fed by hand to satiation three times daily for 16 weeks. Percent weight gain, for fish fed 32, 35, 38, 41, 44, and 47% protein diets were 180.5±43.8, 203.6±32.33, 256.4±19.4, 235.8±20.63, 249.1±19.59, and 275.2±47.3, and specific growth rates 0.91±0.15, 0.98±0.10, 1.13±0.05, 1.08±0.05, 1.11±0.05, and 1.17±0.11, respectively for the study. Biweekly mean weight differences (p ≤ 0.05) occured after week eight, with fish fed 47% diet consistently havingh higher mean wight than those fed 32%. Biweekly weight gain was connsistently different after week two between fish fed 47% and 32% protein. However, fish fed 38 and 44% diets sometimes had significantly more gain than those fed 32 and 35%. Biweekly feed consumption differed after week ten with fish fed 47 and 38% consistently consumed more food than fish fed 32% protein. Feed conversion ratio differences occurred at every period with the most common differences seen between the 32 and 47% groups. This study indicated that growth characteristics could be improved with higher protein diets in juvenile bluegill.
The Distribution of α-Amylase Activity along the Digestive Tract of Juvenile Bluegill (Lepomis macrochirus) and its Comparison with Selected Fish Species
Namrata Giri, Yongfang Zhang, Gregory A. Dudenhoeffer, and Thomas R. Omara-Alwala
Carbohydrates are the least expensive form of dietary energy for animals. Although fish don't have specific requirements for dietary carbohydrates, they must be provided with the appropriate levels of carbohydrates in their diets. Moderate levels of carbohydrate could support fishs' better growth performance and may decrease the use of the more expensive protein and lipids in the diet. Different fish have different ability to utilize digestible carbohydrates, which may relate to the relative amount of amylase activity present in the digestive system of the various species. α-amylase is a key enzyme for carbohydrate digestion. Bluegill, an important forage and recreational as well as a newly emerged food fish, is the most commonly produced sunfish in the North Central Region. Information on the digestive amylase activity and the dietary carbohydrates utilization in Bluegill is lacking. The objective of this study was to determine the distribution of α-amylase activity along the digestive tract of juvenile Bluegill and to compare its activity with slecte fish species. The α-amylase analysis followed Worthington (1993) with a slight modification. α-amylase was detected in the stomach, pyloric cecum, proximal intestine, mid intestine, and distal intestine in Bluegill. The lowest α-amylase activity was found in the stomach. No difference in α-amylase among the three parts of intestine was detected. α-amylase activity in Bluegill along the digestive tract is higher than that in Black Crappie, but significantly lower than that in Grass Carp (p < 0.05). Knowledge of α amylase may provide useful information for estimating the carbohydrates level for juvenile Bluegill diets.
The Size Relationship of 12 Days Post-Exodus Larvae with 56 Day Post-Exodus Fingerlings Regarding Growth and Survival in Bluegill (Lempomis macrochirus)
J.L. Schulte and James E. Wetzel
Low survival and quality of early life-stage bluegill is an obstacle to viable production where size may influence weaning efficiency. Herein, we investigate through two trials the effects of fry size 12-d post-exodus on total length, weight, production and survival through 56-d post-exodus. Full sibling broods (trial 1=10, trial 2=6) were reared with feedings of brine shrimp Artemia sp. nauplii (BS) through 12-d post-exodus (PE). Broods of trial 1 were visual sorted 12 d PE into small and large size groups. Fry (n = 25) from each size group were sampled for measured total length (TL) and weight. Starting 14 d PE, a 7-d co-feeding period with a commercial dry feed (#0 crumb) that was continued through 27 d PE with subsequent feedings using a larger version (#1 crumb) of the same diet continuing through 56 d PE (trial end). Broods of trial 2 were split 4 d post-conception into two gorups of pro-larvae (n = 400). Slow growing groups were fed hourly 0800-1700 while fast growing were fed additionally at 0400 and 2200 through 12 d PE. Surviving fish from each size gorup were collected, with random samples (n = 25 fish) measured for TL and weight. Fry (n = 100 where possible) were placed into 151-L aqauriums with slow and fast growing feed regimens maintained through 13-d PE. Culture regimen thereafter was same as trial 1. Fish of both trials were harvested, measured for TL, weight, and survival. The Wilcoxon Signed Rank Test was run one-tailed using SAS. Results of trial 1 indicate size at 12 d was a predictor of TL, weight and survival through 56 d PE (p ≤ 0.156). Size variation at 12 d as a function of genetics is a predictor of growth and survival through 56 d while at least some size variation resulting from early growth rate differences can be overcome by compensatory growth.
Effects of Soybean Meal Substitution for Fish Meal in Diets of Juvenile Bluegill (Lepomis macrochrius)
K. Stuckenschneider, A. Allen, A. Weckenborg, and Gregory A. Dudenhoeffer
Bluegill has potential for production as a food fish. Feed is 40-60% of total production costs. Few studies have been conducted on bluegill replacing fish meal with soybean meal, which is a less expensive plant protein source. The objective of this experiment was to determine the effect of 25, 50, 75% soybean meal substitution of fish meal protein in juvenile bluegill diets. Treatments consisted of a 38% crude protein control diet, and diets with 25, 50, and 75% of fish meal replaced with soybean meal (SB Sub). All diets were insonitrogenous and isocaloric. A completely randomized block design was used with four replications of each treatment. Twelve fish (~22g) were stocked in indoor water recirculating aquaculture system. Fish were fed to satiation at 0800, 1200, 1600h daily excluding Sunday for 14 weeks. No significant differences (P > 0.05) existed among fish between final weight, percent weight gain, and SGR in control and SB Sub diets. Fish fed 50% SB Sub diets significantly outperformed (P < 0.05) fish fed other SB Sub diets. Fish fed 75% SB Sub had lowest final weight, percent weight gain, and feed consumption. This study showed that at least 50% of the fish meal can be replaced with soybean meal without affecting growth.
The Effects of Dietary Protein-to-Energy Ratio on Juvenile Bluegill (Lepomis macrochirus) Growth with Observations of Sexual Dimorphism
K. Vandeloecht, Gregory A. Dudenhoeffer, Yongfang Zhang, and T.R. Omara-Alwala
Bluegill is a promising aquaculture species in the Midwest. males are typically larger than females. However, there is little or no information on nutritional differences between sexes and protein-to-energy ratio. The objective of this study was to characterize the protein-to-energy ratio in juvenile bluegill with observations on gender differences. Bluegill (20-30g) were fed diets consisting of 35% protein with 14, 16, and 18% lipids and 38% protein with 12, 14, and 16% lipids. Four replicates of 12 fish each were fed the diets for 16 weeks. Terminal mean body weights, lengths, liver wights, visceral weights, hepatic somatics indices (HSI), and visceral somatic indices (VSI) were recorded. No differences were found in the mean body weights, lengths, or visceral weights among diets. Increased liver weights, HSI, and VSI were observed in treated with 35% protein. The study revealed sexual dimporphism in body weights, lengths, HSI, VSI, and visceral weights. When data were compared by sexes there were more differences and patterns than among diets compared by the overall means. No differences in the body weights and lengths were found among fish fed different diets. Liver characteristics of fish fed the 35% diets could indicate future fish growth problems. There is a need for further investigation of the effect of gender on feeding trials.
Scott M. Welch, Gregory A. Dudenhoeffer, and Thomas R. Omara-Alawla
Measuring the lenghts and weights of live fish larvae can be tedious and time-consuming. This constraint could be alleviated by preserving the fish larvae in appropriate chemicals for later measurements. There is little or no information on the effects of preservatives on Bluegill larvae. The objective of this study was to determine the effects of five different common preservatives on Bluegill larvae. Individual weights and lengths of fish were measured and then the larvae were preserved for 7 or 26 days. Preservatives were 5% formalin, 10% formalin, 30% ethanol at -19 *C, 70% ethanol, and 90% ethanol. Preliminary average weights of the larvae preserved for 7d were 1.63, 1.30, 4.02, -0.63, and -4.15g in 5% formalin, 10% formalin, 30% ethanol at -19 *C, 70% ethanol, and 90% ethanol, respectively. The average lengths for 26d were -0.63, -0.39, -0.12, -0.03, and 0.22 in 5% formalin, 10% formalin, 30% ethanol at -19 *C, 70% ethanol, and 90% ethanol, respectively. This study indicated that 70% ethanol had the least effect on weights and lengths of Bluegill larvae preserved for 7 and 26d.
Amino Acid Profiles in the Tissues of Juvenile Bluegill (Lepomis Macrochirus) from the Wild and Commercially-fed Fish
Yongfang Zhang, Gregory A. Dudenhoeffer, Namrata Giri, and James E. Wetzel
Amino acid profiles of fish tissues and fish eggs have been extensively investigated in some fish species. Amino acid profiles are helpful in quantifying the indispensable amino acid requirements for these fish. Bluegill is a major forage fish for the largemouth bass (Micropterus samoides) and an important recreational fish throughout the US. The demand for bleugill as a food fish has increased recently. However, the information on the amino acid profiles of its eggs and tissues is lacking. The objectve of this study was to determine the amino acid profiles of the muscles and whole body of the 1-2 g wild and the commercially fed bluegill. Wild fish were obtained from the ponds that relied on the natural food source. Commercially fed fish were grown indoors. Skinless muscles were obtained by dissected both sides of the 1-2 g bluegill. The results showed the lysine was the most abundant indispensable amino acids in muscles and hwole body of both the wild and the farm-raised fish. The proportion of an individual indispensable amino acid to the sum of all detectable amino acids amount was similar for whole body and muscles in wild or raised fish. For whole body or muscle tissue, wild fish contained significantly higher crude protein but lower crude lipid levels than farm-raised bluegill (p<0.05). This study suggested that nutritional history affected tissue proximate compositions.
The Effect of Dietary Protein Level on the Growth Performance and Digestive Protease Activity in Juvenile Bluegill (Lepomis macrochrius)
Yongfang Zhang, Gregory A. Dudenhoeffer, and Thomas R. Omara-Alawla
A 16-week feeding experiment was conducting in an indoor recirculating aquaculture system (RAS) to determine the effects of dietary protein level on the growth and digestive protease activity in juvenile bluegills. Six isocaloric experimental diets were forumalted with 32%, 35%, 38%, 41%, 44%, and 47% levels of protein. Menhdaen fish meal was use as the sole protein source. Juvenile bluegills of 24.91 ± 0.50 g initial weight were distributed into 24 151 L tanks with 12 fish each. Each diet had four replications. Fish were fed to satiation three times a day by hand. At the termination, there no mortalities in fish fed 38% through 47% protein diet. Bluegill fed 38% or 47% protein diet had significant higher body weight gain and specific growth rate (SGR) than fish fed 32% or 35% [rotein diet. No significant differences (p>0.05) were found in weight gain, SGR, and FCR among the fish fed 38% or higher protein diets. Protein efficiency ratio decreased with increasing dietary protein level from 32% to 47%. Acid protease activity of complete digestive tract increased in trend with increasing dietary protein level from 32% to 47%. No significant differences were detected in the protease activity at different pH level among the treatments. The optimal dietary protein requirement for juvenile bluegill was about 38.3%.
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