Strain differences in feed efficiency measured as residual feed intake in individually reared rainbow trout, Oncorhynchus mykiss (Walbaum)

The efficient use of feed for growth and meat production is important for all animal production industries including aquaculture. Residual feed intake (RFI) is an alternative measure of feed efficiency that has been widely used in livestock production. Residual feed intake was calculated as the difference between intake observed and intake predicted on the basis of a bioenergetics model; a low RFI indicates greater efficiency. Residual feed intake offers some advantages as a selection criterion for improving production efficiency over traditional feed efficiency statistics because it is not a ratio and it typically has a larger coefficient of variation. The RFI of individually reared rainbow trout progeny from six different genetic cross‐types was examined for genetic variation. Proximate analysis and nitrogen retention were also evaluated to determine if differences in RFI correlate to differences in body composition and nutrient retention and varied by cross‐type. Differences between cross‐types indicated a genetic component for RFI, with the most efficient fish of approximately 160 g consuming 0.99 g less and inefficient fish consuming 0.05 g more feed per day than expected. Lower RFI was associated with higher growth rates (r=?0.38, P<0.05) and greater nitrogen retention (r=?0.82 P<0.001).     

The consistency of individual differences in growth, feed efficiency and feeding behaviour in African catfish Clarias gariepinus (Burchell 1822) housed individually

Individual variation in growth, feed intake and feeding behaviour has been previously recognized in several fish species. However, there is a lack of information regarding the consistency of such individual differences, which is important to understand the probability of a certain individual trait to be inherent, i.e. genetically linked. The goal of this study is to quantify the consistency of individual differences in growth, feed intake/efficiency and feeding behaviour in African catfish Clarias gariepinus (Burchell 1822). Forty‐eight juvenile fish (58.9±0.4 g) were housed individually for 47 days and weighed every second week. The consistency of growth, feed efficiency (residual feed intake (RFI)) and feeding behaviour (total feeding time (TFT)) was determined using repeatability estimates. Fish exhibited pronounced individual variation in growth (CV=52.8%), feed intake (34.3%) and in the TFT (>100%). The repeatability estimates were 0.55 for growth, 0.70 for feed intake, 0.49 for RFI and 0.81 for TFT. Individual differences in growth were mainly explained by individual differences in feed intake (～80%). Individual differences in feeding behaviour contributed to explain differences in feed intake by affecting the RFI. With increasing TFT, the maintenance levels also increased suggesting that slow eaters were less efficient in feed/energy utilization. The results of this study indicate that individual differences in growth, feed intake/efficiency and feeding behaviour are consistent over time and therefore probably inherent. Moreover, this study may have implications on the use of feeding behaviour as a predictor of feed efficiency in juveniles of African catfish.     

饲料蛋白质水平对马苏大麻哈鱼幼鱼生长指标和饲料系数的影响

为了解在水温7.4～11.3℃的流水池养殖条件下马苏大麻哈鱼(Oncorhynchus masou masou)幼鱼饲料中不同蛋白质水平对其生长指标和饲料利用效率的影响,设计了5组蛋白质水平为40.40％、44.84％、50.16％、54.82％和59.03％的养殖试验,养殖期为150d.试验过程中进行了水质化学指标的...     

Growth, feed conversion efficiency and growth heterogeneity in Atlantic halibut (Hippoglossus hippoglossus) reared at three different photoperiods

Juvenile Atlantic halibut, Hippoglossus hippoglossus (initial weight (SD) 191.3 (±44.7)) g, were reared for 99 days at a constant temperature of 11°C and subjected to three different light regimes from 13 September to 21 December: continuous light (LD24:0), simulated natural photoperiod of Bergen (60°25′N, LDN) and constant 20 h light:4 h dark (LD20:4). The fish reared on the different photoperiod regimes differed in their growth patterns as juveniles exposed to long days, i.e. LD20:4 and LD24:0, exhibited faster growth than those experiencing a natural photoperiod. The LD20:4 group showed the highest average specific growth rate (0.72% body weight day^?1), whereas fish on LDN displayed the lowest average specific growth rate (0.60% body weight day^?1). The final mean weights of the LD20:4 and the LD24:0 groups were 15% and 12% higher than those of the LDN group. Dividing the duration of the experiment into three time periods shows that the LD20:4 and LD24:0 had a higher feed conversion efficiency (FCE) as compared with the LDN group during the first and the last period, while a reversed situation was observed in the second period. Our data indicate a larger variation in growth rates among individuals in the best‐performing groups (here LD20:4 and LD24:0). This may indicate that formation of size hierarchies is more pronounced in groups with more homogenous growth (here LDN). Overall, our findings indicate that extended light regimes result in faster growth and better feed conversion in juvenile Atlantic halibut. In line with findings on other flatfish species, this supports the concept that constant long day:short night or continuous light regimes should be used by the farmer in order to maximize growth and improve feed conversion in Atlantic halibut.     

Effect of glycine betaine, a feed attractant affecting growth and feed conversion of juvenile freshwater prawn Macrobrachium rosenbergii

A feeding experiment was conducted to determine the effect of the feeding attractant, glycine betaine (betaine hydrochloride) on the growth and feed conversion of juveniles of Macrobrachium rosenbergii (deMan) (mean initial weight 1.12 g). Three types of diets were prepared with the incorporation of glycine betaine at 5, 10 and 15 g kg^?1 levels along with an unsupplemented control. After 60 days, weight gain, feed intake and food conversion ratio (FCR) were higher in prawn fed the three glycine betaine‐added diets compared with the control feed. Among the glycine betaine‐added diets, prawn fed glycine betaine at 5 g kg^?1 level showed highest weight gain (2.73 g) by registering 61.5% increase in growth over control and also higher feed intake (5.79 g) and good FCR (2.12). There were highly significant differences (P < 0.01) in weight gain, feed intake, per day growth and FCR among treatments. There was no significant difference (P > 0.05) in survival among treatments.     

黑鲷幼鱼饲料蛋白源氨基酸平衡的研究

以黑鲷幼鱼肌肉的氨基酸组成作为幼鱼饲料中必需氨基酸需要量的标准模式,通过必须氨基酸指数（ＥＡＡＩ）和生物饲养试验结果相结合,对黑钱财幼鱼的９种不同蛋白源酸比的饲料进行了比较研究,对黑钱财幼鱼配合饲料中氨基酸平衡和蛋白质营养价值进行了评估,筛选出个高效饲料蛋白源配方;表明ＥＡＡＩ是鱼用饲料蛋白质营养价值评估和氨基酸平衡研究的一种简便有效的评价指标。     

Feed intake, growth and feed conversion efficiency of Atlantic halibut, Hippoglossus hippoglossus (L.)

The individual food intake of each fish in each of four groups of Atlantic halibut, Hippoglossus hippoglossus (L.) (mean weight: 422 g) was monitored by direct observation over a period of 21 days. Gross feed conversion efficiency (= growth·feed intake^?1), net feed conversion efficiency and maintenance ration were estimated by regression analysis. Specific growth rates were found to be linearly related to weight-specific consumption at a temperature of 8–9°C: growth = 1.922· feed intake ? 0.242. Maintenance ration was 0.126% of body weight day^?1. The gross feed conversion efficiency increased asymptotically with increasing feed intakes and growth rates, and was found to approach 1.9 at high growth rates (0.5 on a dry weight basis). One feeding per day seemed to be sufficient for maximum food intake and growth rate.     

Effect of varying levels of dietary protein on the growth performance and feed conversion efficiency of snakehead Channa striata fry

Six isocaloric test diets, based on fishmeal-groundnut oil cake and containing 350–600 g kg^?1 protein at 50 g kg^?1 incremental levels were fed to snakehead, Channa Striata (Bloch), fry at a rate of 10% of body weight per day under laboratory conditions to determine the effect of varying level of dietary protein on the growth response. On the basis of percentage weight gain, daily weight gain, specific growth rate and daily tissue protein deposition, the dietary protein requirement of fry was found to be 550 g kg^?1 when fish meal was used as the major source of protein. There was a significant increase in carcass protein and a significant decrease in ash content with progressive dietary protein substitution. Fry fed with high protein diets tended to have lower carcass lipid contents and higher moisture contents.     

Photoperiod influences the growth, food intake, feed efficiency and digestibility of red sea bream (Pagrus major)

Two consecutive trials were conducted to investigate the effects of photoperiod manipulation on growth rate, food intake and feed conversion efficiency (Trial 1), and the digestibility of nutrients and energy (Trial 2) in red sea bream, Pagrus major (body weight 19–120 g). Fish were exposed to four photoperiods (6L:6D, 12L:12D, 16L:8D and 24L:0D) with light intensity 1500 lx on the water surface. The fish were fed with a commercial diet to apparent satiation. In Trial 2, 0.5% chromic oxide (Cr₂O₃) was used as an inert marker. Significantly higher weight gain and specific growth rates were observed in fish exposed to a 24L:0D photoperiod followed by 16L:8D, 6L:6D and 12L:12D photoperiods (P < 0.05). Food intake and feed conversion efficiency (FCE) were also significantly higher in fish exposed to 24L:0D followed by 16L:8D, 6L:6D and 12L:12D photoperiods (P < 0.05). Fish exposed to 24L:0D and 16L:8D photoperiods showed significantly higher lipid and energy digestibility than those exposed to a 12L:12D photoperiod (P < 0.05). The results demonstrated that the enhancement of growth performances under 16L:8D and 24L:0D photoperiods were attributed to improved appetite, greater food intake and higher feed conversion efficiency as well as higher digestibility.     

Additive genetic and other sources of variation in growth traits of juvenile black bream Acanthopagrus butcheri

We used a factorial mating design to estimate the contribution of additive genetic, non‐additive genetic and maternal effects to variation in growth traits of black bream Acanthopagrus butcheri (Munro) at 75, 130 and 180 days of age in the hatchery. Maternal genetic and environmental effects were greatest at 75 days of age, accounting for 9.1% of total phenotypic variance in wet weight, 11.4% of variance in standard length and 8.8% of variance in total length. At later ages maternal effects were much reduced, explaining 0.8–3.7% of phenotypic variance in growth traits. Additive genetic effects were greatest at 130 days of age, when they accounted for 17.4% of total phenotypic variance in wet weight, 21.4% of variance in standard length and 18.7% of variance in total length. Additive genetic effects were negligible (<1%) at 75 days of age and 4.8–5.5% of total phenotypic variance in growth traits at 180 days of age. Non‐additive genetic effects (which also included common environmental effects because of families being raised in the same tank) explained 5.8–7.3% of total phenotypic variance in growth traits at 75 days of age, but were much smaller at later ages. Variable stocking densities among tanks up to 75 days significantly affected all growth trait measurements below 180 days of age.     

Short- and long-term differences in growth, feed conversion efficiency and deformities in juvenile Atlantic cod (Gadus morhua) startfed on rotifers or zooplankton

Growth, feed conversion efficiency and frequencies of skeletal deformities were studied in juvenile Atlantic cod (Gadus morhua) that had been startfed on either rotifers (rotifer group) or zooplankton (zooplankton group). After metamorphosis, the fish were reared at four constant temperatures (7, 10, 13, 16°C) or moved successively from 16 to 13 and 10°C (T‐step, average 13.2°C). The zooplankton group had a consistently higher growth rate at all the temperatures studied. Further, the zooplankton group had higher food intake (20%) and higher feed conversion ratio (1.65 vs. 1.31). In addition, a significantly higher incidence of skeletal deformities was found in the rotifer group (14.2%) compared with the zooplankton group (4.1%). After termination of the laboratory study, the fish were reared in sea pens under ambient conditions for 17 months. Final weights of the zooplankton group were consistently larger (between 12% and 14% larger depending on original temperature groups). To verify the growth results, we conducted a follow‐up study where a single egg group was divided into two parts and fed either on rotifers or zooplankton. This study indicated similar growth differences as found in the first study. Overall, our data suggest that different startfeeding diets may be important for long‐term growth, incidence of deformities and quality of juvenile cod. The use of zooplankton can greatly improve long‐term growth and quality of cod juveniles. The study also highlights the advantage of using elevated temperatures in the juvenile phase as this will lead to significantly higher final weights in the adult stage.     

Genetic variation in the growth traits of straight-bred and crossbred black bream (Acanthopagrus butcheri Munro) at 90 days of age

The current slow growth rate of black bream (Acanthopagrus butcheri Munro) impedes their widespread commercial aquaculture across inland southern Australia. We report initial estimates of genetic variation for growth traits at 90 days of age from a diallel cross using two black bream populations. Standard length, total length, and wet weight varied significantly among lines and among half‐sib groups within lines. Differences among half‐sib groups explained 6.8% of the total variance in standard length, 8.3% in total length, and 7.1% in wet weight, giving estimated heritabilities over all lines of 0.27±0.11 for standard length, 0.33±0.13 for total length, and 0.28±0.12 for wet weight. There was no evidence for heterosis in any traits when straight‐bred and crossbred lines were compared. There were high phenotypic (r_P=0.95–0.98) and genetic (r_G=0.63–0.69) correlations among all growth traits.     

Effects of varying rearing temperatures on expression of different trypsin isozymes, feed conversion efficiency and growth in Atlantic salmon (shape Salmo salar L.)

Hatching and start-feeding temperatures affected the expression of different trypsin isozymes in the pyloric caeca of Atlantic salmon. Hatching temperature of 10 °C induced the expression of the common isozyme TRP-2*100, and of 6 °C induced the variant TRP-2*92 (p$<$0.01). In contrast, start-feeding temperature of 12 °C significantly (p$<$0.0001) influenced the expression of the variant TRP-2*92, compared to 6 °C. The frequencies between different trypsin isozyme patterns were not changed at later stages under varied rearing temperatures.The frequency distribution between Atlantic salmon without and with trypsin variants was about 0.4:0.6. The trypsin isozyme TRP-2*92 was the major variant in Norwegian salmon, while the trypsin variant TRP-1*91 was dominant in Scottish salmon, at frequencies of 0.47 and 0.42, respectively. The presence of both the common and either variant trypsin isozymes were important for feed utilization and growth at varying rearing temperatures. Trypsin isozymes are functionally sensitive to different temperatures. The expression of the common trypsin isozyme TRP-2*100 is important when the water temperature is $>$ 8 °C, while it is important for the expression of the variant TRP-2*92 when the water temperature is $\leq$ 8 °C, especially below 6 °C. The variant TRP-1*91 was observed to perform effectively at a wider temperature range than the variant TRP-2*92, but not at temperature $\leq$ 6 °C.Genetic variation in trypsin isozyme pattern is a primary factor affecting food conversion efficiency and growth under different rearing temperatures.     

利用EST-SSR分子标记研究鲤的饲料转化率性状

饲料转化率是重要的经济性状,通过QTL定位获得的紧密连锁标记以及相关基因,是遗传育种的重要工具。本文利用70个鲤的EST-SSR,对鲤全同胞家系92个体的基因组DNA进行扫描,得到符合1∶1孟德尔分离类型的位点48个,3∶1孟德尔分离类型的位点22个。采用拟回交策略对符合1∶1分离的标记与鲤饲料转化率性状进行单标记回归分析。结果表明：HLJE335、HLJE253、HLE547、HLJE92、HLJE203、HLJE231等6个标记与饲料转化率性状相关（P<0.05）。其中,HLJE547和HLJE203两个标记与饲料转化率相关性达极显著水平（P<0.001）,分别解释了表型变异的11.00%、11.00%。应用NCBI数据库,分别对与性状极显著相关的2个ESTSSR标记进行同源性比对,发现标记HLJE547与斑马鱼基因组中编码ATPase, H⁺ transporting, lysosomal的核酸序列同源（同源性为74%）,与斑马鱼编码的ATPase, H⁺ transporting, lysosomal的蛋白序列同源（同源性为92%）。推测ATPase可能通过影响鲤消化与吸收等生物学机制,从而影响鲤的饲料转化效率。     

Dietary Protein and Lipid Requirements for Juvenile Largemouth Bass,Micropterus salmoides

A feeding trial was conducted to evaluate dietary protein and lipid requirements for juvenile largemouth bass, Micropterus salmoides. A 4 × 2‐factorial layout included four protein (420, 450, 480, and 510 g/kg) and two lipid (80 and 120 g/kg) levels. Fish (initial weight 8.7 g) were fed the test diets for 8 wk. Weight gain, feed intake, feed conversion ratio, hepatosomatic index, and body composition were dependent on dietary protein level. Nitrogen retention efficiency was independent of dietary protein level, lipid level, and their interaction. Weight gain was higher in fish fed the diet containing 480–510 g/kg crude protein than in fish fed the diet containing 420–450 g/kg crude protein at two dietary lipid levels. The feed intake and weight gain were higher in fish fed the diet containing 484 g/kg crude protein and 115 g/kg crude lipid than in fish fed the diet containing 478 g/kg crude protein and 77 g/kg crude lipid. This study indicated that the suitable dietary protein and lipid levels for largemouth bass are 480–510 g/kg and 120 g/kg, respectively.     

摄食促进物质对真鲷摄食和生长的影响

将甘氨酸 丙氨酸 组氨酸 精氨酸、甘氨酸 丙氨酸 组氨酸 精氨酸 甜菜碱、甘氨酸 丙氨酸 缬氨酸、甘氨酸 丙氨酸 缬氨酸 甜菜碱作为摄食促进物质，分别添加到真鲷配合饲料中饲喂真鲷，探讨摄食促进物质对真鲷摄食和生长的影响。结果表明，添加摄食促进物质不仅可促进真鲷的的摄食性，增加其摄食量，还可以提高真鲷的增重率、饲料效率、蛋白效率。添加甜菜碱对促进真鲷的摄食性无作用，但可促进真鲷的生长。     

A proposal for modelling the thermal‐unit growth coefficient and feed conversion ratio as functions of feeding rate for gilthead sea bream (Sparus aurata,L.) in summer conditions

Modelling growth as a function of feeding rate (FR) could be one of the most important tools for fish farms, because this knowledge allows growth to be maximized, or the feed conversion ratio (FCR) to be minimized, thereby improving profits. All growth models should include the three principal variables involved in growth: initial body weight, temperature and feeding rate. The thermal‐unit growth coefficient (TGC) already includes water temperature variation and initial body weight. Studying variation in TGC for fish fed the same diet, but at several feeding rates provides interesting information for modelling. Six different trials were conducted where gilthead sea bream of several different initial weights (24, 38, 50, 110, 220 or 289 g) were fed increasing amounts, and growth and the conversion index response were measured. The TGC response was modelled as a function of FR, and both asymptotic and quadratic responses were examined. The asymptotic model, TGC × 1000 = 2.037*(1?e ^{(?0.8*(FR?0.22)}), had an adjusted R² value of 96.18, whereas the quadratic model, TGC × 1000 = ?0.381 + 1,715 × FR?0,382 × FR², had an adjusted R² value of 96.42. Simulations of the FCR and the economical profitability index (EPI) were conducted to provide tools for maximizing efficiency and profitability, and the results suggest that these tools will be useful for future investigations.     

头足类遗传变异研究进展

头足类在分类上属软体动物门头足纲动物 ,主要包括乌贼、枪乌贼、柔鱼和蛸四大类 ,全部海产。近几十年来 ,它逐步成为世界主要的海洋渔业之一 ,尤其在无脊椎动物中占有重要地位。 1978- 1988年间 ,全世界头足类产量已达 2×10 6ｔ[1] 。头足类具有高营养、生活史较短 (通常为一年 )和生长快等特点 ,是一类很有前途的海水养殖种类和海洋中最大、最具潜在价值的蛋白质资源[2 ] ,而且占据着海洋生物食物链举足轻重的位置。现存的头足类种类有 983种 ,共计 2 0 6属 ,有效种名的 6 5 0种左右[3 ] 。我国是世界捕捞头足类的主要国家之一 ,而且有丰…     

The suitable dose of gamma irradiation on soybean meal as a fish meal substitute in diets for golden pompano (Trachinotus ovatus)

A 5‐week feeding trial was conducted to assess the effect of gamma ray irradiation treatment on soybean meal as a fish meal substitute in diets for golden pompano (Trachinotus ovatus). A diet containing 32% fish meal served as a reference (C), and 75% of the fish meal was replaced by soybean meal that either received no gamma ray irradiation (R0) or was irradiated with gamma ray at a dose of 5 (R5), 10 (R10), 15 (R15), 30 (R30) or 60 (R60) kGy respectively. All the diets were formulated to contain 46% crude protein and 6.5% crude lipid. The weight gain was higher in fish fed diets R5, R10, R15 and R30 than in fish fed diet R0. The feed intake was higher in fish fed diets R15, R30 and R60 than in fish fed diets R0, R5 and R10. No significant differences were found in feed conversion ratio, nitrogen retention efficiency, condition factor, hepatosomatic index, body composition, waste outputs of nitrogen and phosphorus between fish fed the diets with non‐irradiated soybean meal or irradiated soybean meal as the fish meal substitute. Proteins with heavy molecular weight in soybean meal were degraded, whereas the contents of proteins with light molecular weight or peptides increased with the increase in the irradiation dose. This study reveals that gamma ray irradiation at a dose of 5 to 15 kGy can significantly improve the level of soybean meal inclusion as a fish meal substitute in diets for golden pompano.