Two feeding trials were conducted with juvenile largemouth bass Micropterus salmoides to evaluate alternative plant and animal source proteins for their ability to replace fish meal in practical diets. The first trial was designed to identify the most promising candidates. The second trial was conducted to evaluate how much of the fish meal could be replaced by those candidates. In Study 1, feed‐trained largemouth bass (3.1 ± 0.7 g) were randomly stocked into 18114‐L glass aquaria at 25 fish per aquarium. Fish were fed one of six experimental diets, each containing approximately 38% crude protein and 10% crude lipid, to apparent satiation twice daily. The control diet (CTL) contained 30% fish meal and 34.5% soybean meal. Diets 2–6 each contained 15% fish meal and at least 34.5% soybean meal with the remainder of the protein made up of either meat and bone meal (MBM), soybean meal (SBM), poultry by‐product meal (PBM), a 50150 mixture of blood meal and corn gluten meal (BM/CG), or 50150 mixture of hydrolyzed feather meal and soybean meal (FMISBM). There were three replicate aquaria per dietary treatment. After 12 wk, there was no significant difference (P > 0.05) among treatments in survival which averaged 92% overall. Only fish fed the PBM or BM/CG diets had average individual weights and feed conversion efficiencies that were not significantly different (P > 0.05) from the control diet (CTL). In Study 2, the formulation of the control diet (CTL) remained the same. Based on their performance in the first trial, PBM and BM/CG were chosen to now replace 75 or 100% of the fish meal. Fish were stocked at an average weight of 6.9 ± 1.7 g. After 11 wk, fish fed diets containing the BM/CG mixture at both levels were significantly smaller (P 5 0.05) than fish fed other diets and at 100% replacement survival was reduced. Fish fed diets containing poultry meal as the primary protein source performed as well as those fed the control diet (CTL). It appears that PBM can completely replace fish meal in diets for juvenile largemouth bass without adverse effects on growth, feed efficiency, or body composition.

The freshwater prawn Macrobrachiurn rosenbergii is a commercially important culture species in the South Central United States. Two major constraints in the commercial culture of the freshwater prawn in the U.S. are poor survival during live transportation of seed-stock to growout ponds, and live transportation of pond harvested prawn to distant live markets due to the territorial and cannibalistic nature of prawn. The use of anesthetics could possibly improve transport survival; however, to date anesthetic agents have not been evaluated for use with prawn. Two trials were conducted with juvenile freshwater prawn to compare the efficacy of anesthetics commonly used on fish. The first trial was designed to identify the most promising candidates. In Study 1, tricaine methanesulfonate (MS-222), 2-phenoxyethanol, quinaldine sulfate (quinaldine), clove oil, and Aqui-STM were evaluated at 25 and 100 mg/L for 1 h in three replicate 10-L glass containers, containing five juvenile prawn each. Relative sedation level was determined every 3 min for 1 h, then recovery time and survival were measured. In Study 1, MS-222 and 2-phenoxyethanol were determined to be ineffective on prawn at all rates tested. Based on their performance in Study 1, quinaldine, clove oil, and AquiSTM were evaluated at 100, 200, and 300 m f i in Study 2. Observations were determined as in Study 1. Clove oil and AquiS" induced anesthesia faster and at lower concentrations than quinaldine. At the highest treatment rate (300 m e ) prawn suffered 60% mortality in the Aqui-S" treatment, 13% mortality in the quinaldine treatment, and 0% mortality in the clove oil treatment and control following a 1-h exposure to these concentrations. Based on these data, AquiS" and clove oil applied at 100 mg/L may be suitable anesthetic treatments for prawn. Additional research is needed to determine optimal time and dose relationships to minimize stress during holding, handling, and transportation of prawn. Zar, J. H. 1984. Biostatistical analysis, 2nd edition.

Excessive carbohydrates (CHO) in diets for largemouth bass (LMB), Micropterus salmoides, are suspected of accumulating glycogen in hepatocytes, which may result in liver dysfunction. This study evaluated the effect of graded levels of dietary CHO on growth, survival, and liver histology of LMB. One hundred feed-trained advanced fingerling LMB (128.5 6 21.5 g) were stocked into each of nine 3400-L polyethylene tanks. Tanks were randomly assigned one of three experimental diets containing different CHO levels (13, 19, or 25% of diet). The extruded diets were approximately isonitrogenous (42% crude protein) and isocaloric (3 kcal/g energy). There were three replicate tanks per dietary treatment. Bass were fed to apparent satiation twice daily for 148 d. Survival was significantly higher (P # 0.05) for fish fed the 13 and 19% CHO diets (89 and 90%, respectively) compared to those fed the 25% CHO diets (82%). Average harvest weight of fish fed the 13% CHO diet (380 g) was significantly greater (P # 0.05) than for fish fed other diets. Average harvest weight of fish fed the 19% CHO diet (347 g) was significantly greater (P # 0.05) than for fish fed the 25% CHO diet (310 g). Specific growth rates (%/d) were significantly higher (P # 0.05) in fish fed the 13 and 19% CHO diets than in fish fed 25% CHO diet. Feed conversion ratios for fish fed the 13 and 19% CHO diets (2.3 and 2.4, respectively) were both significantly lower (P # 0.05) than in fish fed the 25% CHO diet (3.6). There were no significant differences (P . 0.05) in condition factor, protein efficiency ratio, hepatosomatic index, or liver glycogen concentration among fish fed the different experimental diets. Overall, mean blood glucose levels in fish fed the 13 and 19% CHO diets (61.0 and 71.2 mg/dL, respectively) were significantly lower (P # 0.05) than in fish fed the 25% CHO diet (87 mg/dL). Histopathological examination of livers from fish fed the three diets was used to score the degree of vacuolization of hepatic tissues (0 5 normal, 1 5 slight, 2 5 mild, 3 5 moderate, and 4 5 severe). Regression of vacuolization scores on dietary CHO levels was statistically significant (P # 0.05) and indicated a direct positive relationship between liver vacuolization and dietary CHO level (R 2 5 0.57). These data indicate that LMB grow faster and use feeds more efficiently when CHO are maintained at ,20% of diet. CHO levels .20% negatively impacted liver histology, but a liver tissue analyses did not document glycogen accumulation.

Abstract.-The effects of feeding diets supplemented with oils of varying sources and fatty acid compositions on growth, survival, and biochemical composition of juvenile largemouth bass Micropterus salmoides were evaluated under controlled conditions in aquaria for 12 weeks. Feed-trained juvenile largemouth bass (15.7 6 0.6 g) were stocked into eighteen 114-L glass aquaria at 25 fish/tank and were fed one of five experimental diets (3 replicate aquaria/diet). All diets were formulated to be approximately isocaloric (4,200 kcal gross energy per kilogram) and isonitrogenous (40% crude protein), containing protein primarily from solvent-extracted fish meal and soybean meal. Each diet was supplemented with 5% oil (by weight) using lipids from various sources and with different fatty acid compositions. These included fish oil, corn oil, sunflower oil (high oleic), linseed oil, and a fungal oil (high arachidonic acid). Fish were fed twice daily to apparent satiation. At the end of the study period, there were no significant differences (P . 0.05) between treatment groups in terms of survival (98%), weight gain (595%), specific growth rate (2.2% per day), feed conversion ratio (1.5), percent protein deposited (28%), or hepatosomatic index (2.3). Whole-body proximate composition was not significantly affected (P . 0.05) by source of added lipid, but whole-body fatty acid composition showed large differences and primarily reflected the fatty acid compositions of added oils. Largemouth bass may be able to use diets containing vegetable-and animal-source lipids, which are less expensive than the previously recommended fish oil.

The effects of water temperature on growth rate, survival, and biochemical composition c juvenile largemouth bass Micropterus salmoides were evaluated under controlled conditions in tanks for 12 wk. Feed-trained juvenile largemouth (9.1 2 1.9 g) were stocked into nine 3,610-L polyethylene tanks inside a greenhouse structure a t 140 fish/m3 (500 fish/tank). Three treatment temperatures were evaluated (20,26, and 32 C) with three replicates per treatment. Bass were fed to apparent satiation twice daily using a commercially available floating salmonid diet (45% crude protein and 16% lipid). After 97 d bass grown a t 26 and 32 C had significantly higher (P < 0.05) average weights, SGR, condition factor (K), and production rates (kg/m3) than those in the 20 C treatment. Bass in the 26 C treatment had significantly lower (P < 0.05) FCR and higher percent protein deposit (PPD) than bass raised at 20 and 32 C, which were not significantly different (P > 0.05). There were no significant differences (P > 0.05) in survival among treatments which averaged 97%, overall. Bass raised at 32 C had higher (P < 0.05) lipid levels in the liver than other treatments. Whole body amino acid concentrations were not significantly impacted (P > 0.05) by culture temperature. Largemouth bass raised at 26 C had significantly lower (P < 0.05) levels of stearic acid (18:O) and significantly higher (P < 0.05) levels of arachidonic acid (20:4 n-6) than bass raised at 20 or 32 C. Bass raised at 32 C had significantly higher (P < 0.05) levels of Linoleic acid (18:2 n-6), total saturates, and dienes than bass raised at 26 or 20 C. These data indicate that growth and feed conversion efficiency are reduced at 20 C. Growth is similar at 26 and 32 C, but feed and dietary protein are more efficiently utilized at 26 C.