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1.
The effects of dietary protein (25%, 30%, 35%, 40% and 45%) on growth, survival, feed conversion ratio (FCR), protein efficiency ratio (PER) and body composition were investigated for four sizes (0.51, 45, 96 and 264 g) of Nile tilapia, Oreochromis niloticus L. In all four experiments, there was a progressive increase in growth with increasing dietary protein. In fry (0.51 g), significantly higher growth, survival and feed conversion were recorded for fish fed 40–45% rather than 25–35% protein diets. Similar trends for growth and FCR were also noted in 45 g fish. For larger (96 and 264 g) tilapia, significant differences in growth and FCR were found only between fish fed 25% and 30–45% protein diets. FCR and PER decreased with increasing weight of fish, and both were found to be negatively correlated with dietary protein level. Whole-body composition of the smallest fish was significantly influenced by dietary protein content. Percentage body protein of the fish fed 40–45% protein was higher than that of fish fed 25–35% protein diets, whereas lipid content decreased with increasing dietary protein level. In 45 g fish, both protein and lipid contents were higher in fish fed 25% and 30% protein diets than in those fed 35–45% protein diets. In larger tilapia, no significant influence of dietary protein level on body protein content was found. Percentage lipid decreased with increasing dietary protein level, and no definite trends in ash content were found. The results of these studies indicate that O. niloticus fry (0.51 g) should be reared on a practical diet containing 40% protein, and larger tilapia (96–264 g) on a diet containing 30% protein.  相似文献   

2.
To examine the effects of dietary lipids on the growth and feed utilization of jade perch juveniles, Scortum barcoo, diets containing 36.3% crude protein supplemented with increasing lipid levels (6, 9, 12, and 15% of the dry matter) were used to feed triplicate groups of 30 fish for 60 d. At the end of the experiment, more than 95% fish survived well from all diet groups (P > 0.05). Measurements on the weight gains and the daily specific growth rates indicated that fish fed with diets of 12 and 15% lipids exhibited higher growth rates (P < 0.05); evaluations for the feed conversion ratio and the protein efficiency ratio indicated that fish fed with 12 and 15% lipid diets used their feed and dietary proteins more efficiently (P < 0.05). The muscle lipid and dry matter contents increased dramatically in fish fed with higher dietary lipid levels (P < 0.05). The highest lipid contents were obtained from fish in the 15% lipid diet group and the highest amount of dry matters from the 12% lipid diet group. On the other hand, protein contents in fish muscles declined with increasing dietary lipid levels (P < 0.05), and the lowest values were shown in the 15% lipid diet group. Ash contents showed no significant differences from muscles of fish fed with four different diets (P > 0.05). Together, increasing lipid levels in fish diets was effective to improve fish growth, feed efficiency, and protein utilization.  相似文献   

3.
This study was conducted to evaluate the effect of various dietary protein regimes on growth performance, feed utilization and whole-body chemical composition of Nile tilapia, Oreochromis niloticus (L.). Twenty cages (1 m3 each) were randomly allocated to a four-replicate experiment to represent five treatments (T1–T5) where fish were randomly stocked at a rate of 50 fish (1.5–2.2 g) per cage. Fish in T1–T5 fed on a 45% crude protein (CP) diet for the first 4 weeks. In T1, T2 or T3 fish fed on 45%, 35% or 25% CP diets for the last 8 weeks respectively. In T4 fish fed 35% CP diet for the second 4 weeks followed by 25% CP diet for the last 4 weeks and in T5 fish fed 25% CP diet for the second 4 weeks followed by 35% CP diet for the last 4 weeks. Diets were offered to satiation and provided manually twice a day in the morning and in the afternoon, 6 days a week. The optimum fish growth and feed utilization were obtained at T1, T2 and T4. Protein efficient ratio and apparent protein utilization were lower at T1 and T2 than those of T3–T5. On the other hand, no significant changes in energy utilization were observed among the different treatments. There were no major changes in the carcass composition except in ash content, which was higher in T3 and T5 only. This study recommended that the dietary protein regime is an important management in tilapia culture, and the protein level could be reduced from 45% to 35% then to 25% on increasing the fish size.  相似文献   

4.
Abstract. Semipurified diets containing either 25% or 30% crude protein (CP) from soy isolate (soy) or 30% CP from casein and gelatin (casein) were supplemented with either of two levels of L-lysine HCI (0 or 0·5% of diet) in a 3 × 2 factorial arrangement and fed to fingerling channel catfish, Ictalurus punctatus (Rafinesque), in aquaria for 8 weeks. Factorial analysis of variance indicated a significant ( P < 0·001) positive effect of lysine on weight gain, protein conversion efficiency (PCE) and feed efficiency. Fish fed the soy diet containing 25% CP showed increased weight gain of 24% with lysine supplementation while fish fed soy and casein diets containing 30% CP showed increases of 11 % and 3%, respectively. However, supplementing the 25% CP soy diet with 0–5% L-lysine HCI did not enhance growth performance to the level offish fed the unsupplemented 30% CP soy diet. Significant effects of dietary protein levels and sources on weight gain, PCE, feed efficiency, haematocrit, hepatosomatic index (HSI; % liver weight), intraperitoneal fat (IPF) ratio, dry matter of fillet and whole-body, as well as lipid and protein content of whole-body tissue, were also observed. Fish fed the casein diet containing 30% CP had the greatest weight gain, PCE, feed efficiency, haematocrit and whole-body protein values and lowest IPF ratio and whole-body lipid values compared with those of fish fed the soy diets. Supplemental lysine did not affect body condition indices or proximate composition of whole-body and fillet tissues of fish fed the different protein sources. Therefore, based on this study, dietary protein levels and sources significantly influenced performance characteristics of channel catfish and supplemental lysine was most beneficial at a reduced CP level.  相似文献   

5.
Yeasts used as a probiotic in fish diets could stimulate fish resistance against bacterial infection and could enhance the activities of digestive enzymes in fish guts. In addition to yeast importance, dietary protein is another important part in fish diets that should be carefully optimized to meet fish requirement. It is proposed that the yeast supplementation may enhance the dietary protein turnover and reduce the protein requirement for fish. Therefore, the interactive effects of dietary protein and yeast levels on the growth performance of Nile tilapia, Oreochromis niloticus (L.) fry and their challenge against Aeromonas hydrophila infection was evaluated. In the present study, ten experimental diets were formulated to contain either 35% or 45% crude protein (CP). For each protein level treatment, bakery yeast (Saccharomyces cerevisiae) was supplemented at 0.0, 0.50, 1.0, 2.0, or 5.0 g/kg diet. Fish (0.25–0.48 g) were distributed at a rate of 25 fish per 140-L aquarium. For each diet, triplicate aquaria were fed twice a day, 5 days a week for 12 weeks. Fish growth and feed utilization were significantly affected by either dietary protein or yeast levels alone, while no significant effect of their interaction was observed. The highest fish growth was obtained at 1.0–5.0 g yeast/kg diet at both protein levels; however, the fish performance at 45% CP was better than that fed on 35% CP diets. The optimum feed conversion ratio (FCR) was obtained when fish fed on 1.0–5.0 and 2.0–5.0 g yeast/kg diet at 35 and 45% CP, respectively. The cumulative fish mortality, after interperitoneal injection with A. hydrophila for 10 days, and bactericidal activity was significantly higher in fish fed 35% CP diets than those fed 45% CP diets. Both variables decreased significantly with the increase in yeast levels. The lowest bacterial count and bactericidal activity were obtained in fish fed 5.0 g yeast/kg diet irrespective to dietary protein levels. It could be concluded that the inclusion of live bakery yeast in practical diets could improve the growth performances, feed utilization, and physiological status of Nile tilapia fry and their challenge against A. hydrophila infection. Moreover, fish performance when fed 45% CP diet was better than those fed 35% CP diet. Based on these results, the most suitable yeast level for maximum Nile tilapia growth was determined to be 2.0 g yeast/kg diet with 45% CP diet; however, this level was recommended to stimulate their productive performance and enhances their resistance against A. hydrophila infection.  相似文献   

6.
This study was conducted to evaluate the use of gambusia, Gambusia affinis, fish meal (GFM) in practical diets for fry Nile tilapia, Oreochromis niloticus (2.11 ± 0.11 g). Six isonitrogenous diets (35%) were formulated in which GFM replaced 0.0, 10, 25, 50, 75, or 100% of the protein supplied by herring fish meal (HFM). Fish were fed one of the test diets at a feeding rate of 4% of the fish body weight 6 d a week, 2 times a day for 13 wk. Results demonstrated that fish growth increased with increasing GFM up to 75%, which produced the highest growth of the treatments. The lowest fish growth was obtained at 100% GFM. Feed intake (FI), protein efficiency ratio (PER), and apparent protein utilization (APU) increased significantly, while feed conversion ratio (FCR) decreased significantly with increasing GFM up to 75%. FI, PER, and APU decreased significantly, while FCR increased significantly for diets containing 100% GFM. There were no significant differences in moisture, protein, lipid, or ash contents in final fish body following inclusion of GFM in fish diet. There was no significant difference in the digestibility coefficient of dry matter. The digestibility coefficients of protein and gross energy for diets containing 100% GFM replacement were the lowest as compared with other GFM levels. The present study recommended that GFM is a suitable protein source in practical diets for fry Nile tilapia and could replace HFM up to 75%.  相似文献   

7.
A feeding trial was conducted to investigate the effects of dietary lipid level on growth and body composition of juvenile river chub, Zacco barbata (Regan). Juvenile river chub with 0.26 g body weight were given five isoenergetic and isonitrogenous purified diets containing 0–20% lipids in 5% increments for 8 weeks. The dietary lipid source was a 1:1 (w/w) mixture of menhaden fish oil and soybean oil. There was no significant difference on weight gain, feed conversion ratio, or protein efficiency ratio, among fish fed different experimental diets ( P  > 0.05). Body fat contents of both initial fish and fish fed the diet containing 20% dietary lipid were significantly greater than those fed other diets ( P  < 0.05). The percentage of total n -3 fatty acids in the body lipids of fish at the beginning of the trial was 12.34%. This value decreased to 3.83% by the end of the trial for fish fed a control diet with no supplemented lipid. Similar trends were observed in linoleic acid contents that were 6.11% and 3.09%, respectively, for initial fish and the fish fed the control diet for 8 weeks. However, the absolute amount of these fatty acids stayed the same in the initial and in the control group. Meanwhile, as dietary lipid level increased, the percentages of these fatty acids in body lipids of fish at the end of the trial also increased.  相似文献   

8.
Dietary protein and lipid effects on growth, body composition and indices of iridescent Shark Pangasius hypophthalmus (Sauvage 1878) fry were studied using a 4 × 2 factorial design. Triplicate groups of 10 fish per tank, with initial mean weights of 3.54–3.85 g were fed eight isocaloric diets comprising a combination of four protein levels (250, 300, 350 and 400 g kg−1 or 25%, 30%, 35% and 40%) and two lipid levels (60 and 120 g kg−1 or 6% and 12%) respectively. The fish were hand-fed to satiety twice daily for 8 weeks. Specific growth rate (SGR) and feed conversion ratio (FCR) showed significant effects ( P <0.05) with variations in dietary protein and lipid. The highest SGR was observed in fish fed 40% protein/12% lipid diet but this value was not significantly ( P >0.05) different from the fish fed 30% protein/12% lipid diet. The FCR was lowest for the 40/12 diet and differed significantly only with the 25/6, 25/12 and 30/6 treatments respectively. The hepatosomatic index (HSI) was significantly affected by the level of protein, but intraperitoneal fat (IPF) showed significant variation due to dietary lipid level. The HSI significantly ( P <0.05) decreased when dietary protein increased from 25% to 30% but increased marginally thereafter. The IPF values increased with increased dietary lipid but decreased with increased dietary protein. Body protein was positively correlated with dietary protein content; conversely, body lipid content decreased with increase in dietary protein. The results of this experiment indicate the presence of a protein-sparing effect of lipid as fish fed 30% protein/12% lipid diet had growth and feed utilization comparable to those fed 40% protein/12% lipid diet.  相似文献   

9.
不同蛋白水平饲料对台湾东风螺生长性能和体组成的影响   总被引：3，自引：0，他引：3  
以优质鱼粉、豆粕等原料制成蛋白质含量不同的6组饲料(粗蛋白含量分别为48.16%、45.64%、40.67%、35.68%、30.80%、25.96%),喂养台湾东风螺47 d,以投喂鲜杂鱼组作为对照,分别于15、27、37、47 d测定螺高、螺宽、螺体重等生长指标,计算不同处理组在不同时间段(27、37、47 d)的饲料系数和蛋白质效率,试验结束后测定东风螺螺肉的体组成和氨基酸含量,研究结果表明:投喂颗粒饲料比投喂鲜杂鱼的饲料系数显著高;而当颗粒饲料中蛋白质含量变化(25%~48%)时,对东风螺生长性能并无显著影响。但随着饲料蛋白含量的增加,东风螺对饲料的利用率在一定程度上有所提高。当饲料中粗蛋白含量低于25%时,47 d时其饲料系数2.3,显著高于其他饲料组;蛋白质效率1.74显著低于蛋白含量48.16%饲料组。从东风螺生长性能和饲料利用分析,颗粒饲料中蛋白质含量不应低于25%。所有组东风螺螺肉的粗蛋白、脂肪,总氨基酸组成均无显著差异,但是一些中性氨基酸(如亮氨酸、异亮氨酸和丙氨酸)和精氨酸随着饲料蛋白含量的降低而呈现出降低趋势,部分组产生了显著差异。投喂颗粒饲料的东方螺生长不如投喂鲜杂鱼组。  相似文献   

10.
A feeding trial was conducted to study the effect of six iso‐energetic diets containing 25, 30, 35, 40, 45 and 50% crude protein (CP) on growth, survival and feed conversion ratio (FCR) as well as the protein requirement of an endangered cyprinid, Tor putitora. Triplicate groups of fingerlings with initial total length of 10.0–11.0 cm and weight of 12.0–12.5 g were reared in earthen ponds and fed diets at 5% of body weight for 120 days. Performance was evaluated on the basis of total length gain, body weight gain, survival rate, feed efficiency, FCR, protein efficiency ratio, specific growth rate, energy retention, gross and net yield in kg ha?1. Whole‐body carcass composition of fish was analysed at the start and the end of the experiment. Growth and FCR were influenced significantly (P<0.05) by dietary CP contents; higher growth and lower FCRs were obtained with increasing dietary protein. Dietary protein also influenced the whole‐body carcass composition of the fish. Higher protein and ash, and lower moisture and lipid in the whole body were observed with increasing dietary protein. Broken‐line regression analysis indicated that the optimum dietary protein level for maximal growth of mahseer lies between 45% and 50% (45.3%). Overall feed utilization and growth performance of the fish is comparable to that of other aquaculture species and the fish offers high potential for commercial aquaculture.  相似文献   

11.
An 8‐wk feeding trial was conducted to evaluate the effects of varying dietary protein and lipid levels with different protein‐to‐energy (P/E) ratios on growth, feed utilization, and plasma biochemical parameters of Sinocyclocheilus graham. Nine experimental diets were formulated to contain three protein levels (35, 40, and 45%), and each with three lipid levels (4, 8, and 12%), to produce a range of P/E ratios from 71.31 to 98.64 mg protein/kcal. Each diet was randomly assigned to triplicate groups of 25 fish. Fish grew best when fed the diet containing 45% protein and 12% lipid. However, fish fed the diet with 40% protein and 8% lipid had similar weight gain and specific growth rate as those fed the above diet but showed relatively better feed conversion ratio, protein efficiency ratio, and protein and energy retentions. Additionally, plasma total amino acids and blood urea nitrogen contents and γ‐glutamyltransferase, aspartate aminotransferase, and alanine aminotransferase activities in fish fed the diet containing 40% protein and 8% lipid were relatively low among the dietary treatments. These results may indicate that a diet containing 40% protein and 8% lipid with P/E ratio of 84.05 mg protein/kcal would be suitable for the optimal growth, feed utilization, and health of S. graham.  相似文献   

12.
A fish feeding trial was conducted in a warm‐water recirculating system for 8 weeks to assess the nutritive value of processed mucuna seeds as a dietary protein replacement for fish meal in practical diets of tilapia. Diets 2–6 contained mucuna seeds processed as follows: raw, soaked in water, soaked in sodium bicarbonate solution (0.07%), soaked in ascorbic acid solution (0.1%) or soaked in water containing 3% of freeze‐dried moringa leaf powder, followed by autoclaving. The mucuna seed meals were then used to replace 25% of the total dietary protein in each diet. The performance of fish fed these diets was compared with fish fed a fish meal‐based control diet (diet 1), which contained 35% protein. All diets were prepared to be isonitrogenous and isoenergetic. Each treatment had three replicates, using seven fish per aquarium, with a mean initial body weight of 3.9 ± 0.06 g. Fish were fed five times about their maintenance level (3.0 g feed × body weight (kg)?0.8 day?1), and no mortality was observed during the experiment. The growth rate, feed conversion ratio and protein productive value of fish fed diets 1, 3, 4, 5 and 6 were similar. However, with regard to energy retention and apparent net lipid utilization, the values observed in fish fed diet 1 were similar to those of fish fed diets 5 and 6, and diet 6, and significantly higher than other dietary groups. Fish fed diet 2 showed a significantly (P < 0.05) reduced growth performance, higher carcass moisture and ash contents, and lower levels of lipid and energy compared with all other dietary groups. Fish fed diet 2 had a significantly lower plasma cholesterol level compared with other diets. However, no significant variation of muscle cholesterol was found between the dietary groups. Even though the hepato‐somatic index of the fish fed diets 3, 4, 5 and 6 was significantly lower than diet 1, these values appeared to be significantly higher compared with fish fed diet 2. The present study indicates that the inclusion of mucuna seed meal (replacement of 25% of total dietary protein of feed) after soaking in any one of the tested solutions followed by autoclaving significantly improved the growth performance and feed utilization of tilapia compared with that of the raw seeds. Moreover, these values were similar to the performance obtained with the fish meal‐based control diet 1. This might be due to the relative reduction of anti‐nutrients, particularly the non‐protein amino acid 3, 4‐dihydroxyphenylalanine, and increased palatability and nutrient availability of processed beans.  相似文献   

13.
The effects of various dietary protein levels on growth performance, whole body composition and nutrient utilization were studied in two-banded sea bream ( Diplodus vulgaris ), a candidate species for aquaculture. Fish (initial weight 6.1 g) were fed to satiety six iso-energetic diets, containing 5%, 12.5%, 25%, 35%, 45% or 55% of crude protein during 72 days. Fish fed 35% and 45% protein attained better growth and feed utilization than the other groups ( P  < 0.05). Daily growth index and feed conversion ratio were the poorest for fish fed 5% and 12.5% protein ( P  < 0.001), while the 25% and 55% protein groups had intermediate performance. Lipid retention increased significantly from 13.7% to 30.1% ( P  < 0.0001) and protein retention decreased from 35.5% to 21.3% ( P  < 0.01) with increasing protein levels from 12.5% to 45%. Muscle protein, lipid and energy concentrations were not significantly affected by dietary protein level. The estimated protein requirement for maintenance and maximum growth of two-banded seabream growing from 6 to 20 g were 7.5% and 35.7%, respectively. Protein requirements as calculated from body protein gain were 2.3 and 6.5 g of protein intake per kilogram body weight per day.  相似文献   

14.
This study was conducted to investigate the influence of dietary lipid level and supplemental soy lecithin on growth, feed utilization and body composition of juvenile flounder reared at two suboptimal water temperatures, 12 and 17 °C. Three isonitrogenous (CP 50%) diets containing 1% squid liver oil (S7), 7% squid liver oil (S14), and a mixture of 2% soy lecithin and 5% squid liver oil (SL14) were formulated to obtain 7% and 14% of crude lipid. Triplicate groups of fish (6.3 ± 0.2 g) were fed to apparent satiation twice a day for 60 days. Weight gain, daily feed intake, feed efficiency and protein efficiency ratio were significantly higher for fish reared at 17 °C than at 12 °C. Daily feed intake was significantly decreased with the increase of dietary lipid level at the same water temperature, but weight gain was not affected by dietary lipid composition. At 12 °C, feed efficiency and protein efficiency ratio were significantly higher for fish fed the S14 and SL14 diets than those of fish fed the S7 diet, while at 17 °C feed efficiency and protein efficiency ratio of fish fed the S14 diet, which were not significantly different from those of fish fed the SL14 diet, were significantly higher than those of fish fed the S7 diet. There were no significant effects of dietary lipid composition or temperature range on the whole body contents of moisture, crude protein, lipid or ash. Dietary lipid composition and temperature affected the fatty acid content of the polar lipid from the liver; and the n-3HUFA contents such as 20:5n-3 and 20:6n-3 were higher at 12 °C than at 17 °C. The results of this study indicate that an increase of dietary lipid level from 7% to 14% has beneficial effects on feed utilization of flounder when reared in suboptimal water temperatures. The increase of water temperature from 12 to 17 °C improved growth and feed utilization, but 2% soy lecithin had no substantial effect on growth and feed efficiency of juvenile flounder.  相似文献   

15.
Growth, reproductive performance, muscle and egg composition were investigated in grass carp, Ctenopharyngodon idella (Valenciennnes), fed hydrilla or formulated diets with varying protein levels. Five experimental diets, with varying levels (20%, 25%, 30%, 35% and 40%) of crude protein (CP), were used. One of the fish groups was fed hydrilla. Fish (44.1±0.3 cm; 913±9 g) were stocked (20 tank?1) in outdoor concrete tanks (20 × 10 × 1.5 m) in duplicate, and fed to satiation, twice daily, at 09:00 and 17:00 hours for the experimental duration of 360 days. High (P<0.05) weight gain was recorded in fish fed 30% and 35% CP diets. However, values for gonadosomatic index (GSI), egg diameter, relative fecundity (eggs kg?1 body weight), fertilizability and hatchability (%) were comparable (P>0.05) in fish at ≥25% of dietary protein intake. Hydrilla‐fed fish exhibited lower (P<0.05) values for the measured parameters. Crude protein content in muscle increased with dietary protein level. Highest (P<0.05) muscle protein was obtained in fish fed 35% CP diet. Muscle fat was comparable (P>0.05) among fish receiving formulated diets. Ash content was not significantly (P>0.05) different among fish of different dietary groups. Moisture content in fish fed formulated diets, with the exception of 20% CP diet, did not vary significantly (P>0.05). Eggs of fish fed formulated diets contained higher CP and fat contents than those of hydrilla‐fed fish. High (P<0.05) moisture content was noted in the eggs of hydrilla‐fed fish. Ctenopharyngodon idella fed formulated diet, with a minimum of 25% CP, showed better reproductive performance than those fed hydrilla.  相似文献   

16.
A 12‐week experiment was conducted to evaluate the suitability of gambusia (Gambusia affinis) fish meal (GFM) as a partial and complete substitute for the protein supplied by herring fish meal (HFM) in diets for red tilapia fingerlings (mean weight 0.42 g). Seven isonitrogenous (35% crude protein), isolipidic (9% fat) and isoenergetic (15.9 kJ DE‐g?1 diets were formulated in which GFM replaced 0.0, 10, 25, 50, 75, 90 and 100% of the protein supplied by HFM. In general, GFM exhibited good potential as a substitute for HFM in red tilapia diets with no adverse effects on growth, feed efficiency, body composition, blood parameters or apparent digestibility of dry matter, protein and gross energy compared with the HFM‐based control diet. Growth performance (in terms of final weight, weight gain, per cent increase in weight and growth rate) of fish fed diets containing GFM at 25 or 50% level of replacement for HFM‐protein (diets 3 and 4) was statistically higher than for fish fed diets containing GFM at replacement levels >50%. Diet 4 had the best economic efficiency of fish weight gain. Partial or complete substitution of GFM for HFM did not affect feed utilization efficiency (in terms of FCR, FER, PER and APU) or digestibility coefficients of dry matter, protein and gross energy compared with those of the HFM‐based diet. Apparent protein digestibility varied little between diets, ranging from 84.2 to 87.3% with no significant differences. Survival of fish fed all the experimental diets (except for fish fed GFM at 90 or 100% level of replacement for HFM‐protein) was comparable with that of fish fed the control diet and ranged from 91.7 to 98.3%.  相似文献   

17.
A 6-week feeding trial with four dietary protein levels (22%, 32%, 42% and 52%) and two dietary lipid levels (10% and 19%) was conducted to investigate the optimum dietary protein and lipid level for the growth of bagrid catfish fingerlings (0.92±0.01 g initial weight). Survival of fish was not affected by either dietary protein or dietary lipid level. Specific growth rate of fish fed the diets containing 10% lipid increased with increasing protein level and that of fish fed the diets containing 19% lipid increased with increasing protein level up to 42%. Feed efficiency of fish fed the 42% protein diet with 19% lipid and 52% protein diet with 10–19% lipid was higher than that of other groups. Daily feed intake of fish decreased with increasing dietary protein level at both lipid levels and showed a tendency toward higher values at 10% lipid diets than at 19% lipid diets. Protein efficiency ratio and protein retention of fish decreased with increasing dietary protein level, and those of fish fed the 19% lipid diet were higher than those of fish fed the 10% diet at 42% protein diet. Moisture content of fish fed 10% lipid diets was higher than that of fish fed 19% lipid diets, at each protein level. Crude lipid content of fish fed 19% lipid diets was higher than that of fish fed 10% lipid diets at each protein level. The results of this study indicate that an increase of dietary lipid level can improve growth and protein utilization, and the diet containing 42% protein with 19% lipid would be suitable for optimum growth and effective protein utilization of bagrid catfish fingerlings.  相似文献   

18.
A 56‐day feeding trial was conducted to determine the effects of supplementing diets of juvenile Japanese flounder, Paralichthys olivaceus, with Eucheuma denticulatum (EDP). Isonitrogenous and isolipidic test diets were prepared using a fishmeal‐based positive control diet (PC) and a fishmeal‐soy protein concentrate negative control diet (NC) supplemented with 3 (D3%), 6 (D6%) and 9% (D9%) EDP. The test diets were assigned to tanks (12 fish tank?1, initial mean body weight of 0.42 ± 0.01 g) in triplicates. Results of the feeding trial indicated that growth rates and feed efficiency significantly improved (P < 0.05) when 3% EDP was supplemented in the diets. However, there was a significant reduction (P < 0.05) of growth and feed efficiency in fish fed diets with higher supplementation levels. Protein, lipid, dry matter and ash contents of carcass and their corresponding nutrient retention values were not markedly altered in all dietary treatments. Fish fed diets supplemented with EDP exhibited higher (P < 0.05) omega‐3 polyunsaturated fatty acid accumulation in dorsal muscle when compared with those of fish fed NC. Blood chemical parameters showed significant differences (P < 0.05) in total cholesterol and triglyceride levels. These results suggest that EDP can be efficiently utilized by Japanese flounder and can promote best growth and feed utilization at a level of 3%.  相似文献   

19.
This experiment was conducted to determine the optimum dietary protein level for juvenile olive flounder Paralichthys olivaceus (Temminck et Schlegel) fed a white fish meal and casein‐based diets for 8 weeks. Olive flounder with an initial body weight of 4.1 ± 0.02 g (mean ± SD) were fed one of the six isocaloric diets containing 35%, 45%, 50%, 55% and 65% crude protein (CP) at a feeding rate of 4–5% of wet body weight on a dry‐matter basis to triplicate groups of 20 fish per aquarium. After 8 weeks of feeding, per cent weight gain (WG) and feed efficiency ratios of fish fed the 55% CP diet were not significantly higher than those from fish fed the 50% and 65% CP diets, but significantly higher than those from fish fed the 35% and 45% CP diets. Fish fed the 50%, 55% and 65% CP diets had significant higher specific growth rates than did fish fed the 35% and 45% CP diets; however, there was no significant difference among fish fed the 50%, 55% and 65% CP diets. The protein efficiency ratio was inversely related to the dietary protein level; that is, maximum efficiency occurred at the lowest dietary protein level. Broken‐line model analysis indicated that the optimum dietary protein level was 51.2 ± 1.8% for maximum weight gain in juvenile olive flounder. The second‐order polynomial regression analysis showed that the maximum WG occurred at 57.7% and it revealed that the minimum range of protein requirement was between 44.2% and 46.4%. These findings suggest that the optimum dietary protein level for maximum growth could be greater than 46.4%, but less than 51.2% CP in fish meal and casein‐based diets containing 17.0 kJ g?1 energy for juvenile olive flounder.  相似文献   

20.
Two, 6 week feeding trials were conducted to evaluate the impacts of protein and lipid on weight gain, feed efficiency ratio values and biological indices of juvenile cobia (Rachycentron canadum). Utilizing a 2 × 3 factorial design, experimental diets containing two levels of crude protein (CP; 40 and 50%) and three levels of lipid (6, 12 and 18%), providing 14.4, 15.1 and 16.6 kJ available energy/g dry diet (calculated), respectively, were formulated for use in both feeding trials. In the first trial, cobia (initial weight 49.3 g per fish) was randomly assigned to one of the six experimental diets and fed to apparent satiation twice daily. At the end of the first trial, weight gain in cobia was not significantly impacted by protein levels with values ranging from 333% (50% CP) to 353% (40% CP). However, lipid significantly (P < 0.05) affected weight gain with fish fed the diet containing 18% total lipid returning the lowest growth of 293%. Feed efficiency ratio values were not significantly impacted by dietary protein or lipid levels and ranged from 0.46 (50% CP/18% lipid) to 0.51 (50% CP/6 and 12% lipid). Survival was significantly impacted by protein and lipid with fish fed the diets containing 50% CP and 18% lipid having lower (P < 0.05) survival rates of 90%.In the second trial, smaller fish were utilized (7.4 g average initial weight) under identical experimental conditions and dietary formulations. Weight gain was not significantly affected by protein or lipid levels and ranged from 1099% in fish fed the diet containing 40% CP/18% lipid to 1305% in fish fed the diet containing 50% CP/12% lipid. Feed efficiency ratio values, visceral somatic and hepatosomatic indices were significantly affected by protein and/or lipid. Muscle and liver lipid were impacted by dietary lipid (P = 0.0203 and 0.0012, respectively). Muscle protein was significantly impacted by dietary protein levels, while liver protein was affected by both main effects. Dietary protein and lipid had no impact on muscle ash.These data suggest that juvenile cobia can thrive on a wide range of protein and lipid levels, as well as a range of protein to energy ratios. Positive impacts of optimizing the protein component in terms of economic and environmental concerns, coupled with the ability to maintain the rapid growth rates this species are renowned for at lower dietary lipid levels, point towards beneficial consequences of further refinement of commercial cobia production feeds.  相似文献   

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