Effect of supplemental taurine on juvenile channel catfish Ictalurus punctatus growth performance

Juvenile channel catfish (5.6 g/fish) were fed a basal diet that contained major protein (soybean meal, cottonseed meal) and energy (ground corn grain, wheat middlings) ingredients that were derived from plant sources. The basal diet was supplemented with three levels of crystalline taurine to provide 1, 2 and 5 g/kg taurine. In addition, a fifth diet that contained 80 g/kg menhaden fishmeal formulated with the same plant‐source ingredients was included as the positive control diet. Fish were fed the five diets once daily for 12 weeks. Weight gain was highest in catfish fed taurine at 2 g/kg (47.8 g/fish) compared to catfish fed the control basal diet (40.8 g/fish) and 80 g/kg fishmeal diet (41.1 g/fish) (p < .05). Among the taurine‐supplemented diets, weight gain was lowest in catfish fed taurine at 5 g/kg. Feed conversion ratio (FCR) was significantly improved in fish fed diets supplemented with taurine at 2 g/kg compared to all other treatments (p < .01). Survival during the growth study ranged from 98.0 to 99.0% (p > .05) for all treatments. The results suggest taurine supplementation to juvenile channel catfish may improve weight gain and FCR.     

Evaluation of cottonseed meal derived from genetically modified cotton as feed ingredients for channel catfish,Ictalurus punctatus

Three laboratory experiments were conducted to assess nutritional quality of cottonseed meals from genetically modified (GM) cotton crops, Roundup Ready^® Flex, Bollgard^® × Roundup Ready, Bollgard II^® × Roundup Ready, and Bollgard II × Roundup Ready Flex for channel catfish, Ictalurus punctatus using Good Laboratory Practices. Growth, feed efficiency, survival, and fillet composition of catfish fed diets containing 20% cottonseed meal from these cotton products were compared with that of catfish fed diets containing cottonseed meals from the near‐isogenic, non‐GM control and non‐GM commercial varieties. Juvenile catfish (mean weights of 4.1, 5.0, and 0.6 g per fish for Experiments 1, 2, and 3, respectively) were stocked in each of 80‐L aquaria and fed experimental diets for 8 weeks. Although there were slight variations in proximate composition, amino acids, and gossypol concentrations, the GM cottonseed meals were not significantly different from the conventional control and the reference cottonseed meals. Weight gain, feed conversion, survival, and fillet composition of catfish fed GM cottonseed meals appeared similar to that of either the control or the commercial cottonseed meals. Results from the present study demonstrate that these GM cottonseed meals are nutritionally equivalent to conventional non‐GM cotton varieties when fed to catfish at 20% of the diet.     

Effects of various corn distillers by‐products on growth,feed efficiency,and body composition of channel catfish,Ictalurus punctatus

A study was conducted to examine the use of corn distillers’ by‐products in diets and the effects of additional dietary fat on channel catfish, Ictalurus punctatus, performance. Juvenile channel catfish (initial weight: 12.6 g per fish) were stocked in flow‐through aquaria and fed one of six practical diets for 9 weeks. Fish fed the control + fat diet consumed more diet and had higher feed efficiency ratio (FER) than fish fed the control diet, but weight gain was not significantly different between fish fed these two diets. Fish fed the diet containing 300 g kg^?1 distillers dried grains with solubles (DDGS) consumed more diet and gained more weight, but had similar FER compared with fish fed the control + fat diet. The diet containing 200 g kg^?1 high‐protein distillers grains (HPDDG) resulted in similar diet consumption, weight gain and FER as the control + fat diet. Fish fed the diet containing 100 g kg^?1 distillers solubles (DS) consumed more diet, but had similar weight gain and FER compared with fish fed the 300 g kg^?1 DDGS diet. The presence of distillers solubles in the diet (300 g kg^?1 DDGS, 100 g kg^?1 DS, 100 g kg^?1 EDS diets) appears to increase diet consumption, weight gain, and FER over the control diets with or without additional fat.     

Soldier fly, Hermetia illucens L., larvae as feed for channel catfish, Ictalurus punctatus (Rafinesque), and blue tilapia, Oreochromis aureus (Steindachner)

Abstract. Three feeding trials, involving pre-pupal larvae of soldier fly, Hermetia illucens L., grown on poultry manure, were conducted to assess: (1) channel catfish, Ictalurus punctatus (Rafinesque), response to substitution of dried meal larvae for the fish meal component of the catfish diet and (2) if feeding 100% whole or chopped larvae to channel catfish or blue tilapia, Oreochromis aureus (Steindachner), will support normal growth comparable to those fed a commercial diet. Effects on fish quality were also evaluated. Replacement of 10% fish meal with 10% soldier fly larvae resulted in slower growth over a 15-week period for subadult channel catfish grown in cages (trial 1). However, the replacement did not reduce growth rate significantly when channel catfish were grown in culture tanks at a slower growth rate (trial 2). Feeding 100% larvae did not provide sufficient dry matter or protein intake for good growth for either species grown in tanks (trials 2 and 3). Chopping of the larvae improved weight gain and efficiency of the utilization.     

Effects of black soldier fly (Hermetia illucens) larvae meal protein as a fishmeal replacement on the growth and immune index of yellow catfish (Pelteobagrus fulvidraco)

A 65 days feeding trial was conducted to evaluate the potential of black soldier fly larvae (BSFL) as a fish meal (FM) protein alternative in the diet of yellow catfish. Fish meal protein was replaced with BSFL meal protein at 0% (control), 13%, 25%, 37%, 48%, 68%, 85% and 100%. Compared with the control group, increased growth performances (e.g. weight gain rate increased by 21.7%) and immune indexes (e.g. serum lysozyme activity increased by 6.8%) of yellow catfish fed with diets in which a maximum of 48% FM protein was replaced by BSFL meal protein was determined. The diet in which 25% FM protein was replaced by BSFL meal protein resulted in the greatest growth performances (e.g. weight gain rate increased by 29.1%) and immune indexes (e.g. serum lysozyme activity increased by 31.9%) as well as the lowest feed conversion ratio (0.9) among all diets tested. No significant differences in survival rate, body indexes or composition were determined among all treatments. Therefore, BSFL meal protein has the potential to partially replace FM protein in the diet of yellow catfish, and it may also enhance the immunocompetence of the fish.     

不同饲料料型及投喂频率对斑点叉尾鮰幼鱼生长及肌肉品质的影响

本研究旨在探究不同饲料料型及投喂频率对斑点叉尾鮰(Ictalurus punctatus)生长及肌肉品质的影响。研究采用双因素试验设计,以饲料料型(膨化饲料,EF;颗粒饲料,PF)和投喂频率(2次/日,F2;3次/日,F3)为影响因素,共4个组,分别命名为EFF2、PFF2、EFF3和PFF3,每组3个平行,投喂8周,每天定时投喂两次(7:30和16:30)或3次(7:30, 12:00, 16:30)。结果显示,斑点叉尾鮰的末重和增重率受到投喂频率的影响,F2组显著高于F3组(P0.05);而饲料料型则对斑点叉尾鮰的生长无显著影响(P0.05)。颗粒饲料组的肌肉粗脂肪含量和内聚性、回复性显著低于膨化饲料组(P0.05),而硬度显著高于膨化饲料组(P0.05)。F3组的肌肉硬度、胶着性和咀嚼性则显著高于F2组(P0.05)。颗粒饲料组生肌调节因子5 (myogenic factor 5, Myf5)和肌肉生长抑制素(myostatin,MSTN)基因的相对表达量显著低于膨化饲料组(P0.05)。F3组肌肉中MSTN基因相对表达量显著高于F2组,而肌细胞生成素(myogenin,MyoG)基因相对表达量则呈现相反趋势。综上,投喂同种配方的膨化饲料和颗粒饲料对斑点叉尾鮰的生长效果相似,但是投喂颗粒饲料的斑点叉尾鮰硬度更大,而投喂膨化饲料则肌肉脂肪含量更高;斑点叉尾鮰的最佳投喂频率是每天2次。     

Effects of short-term feed restriction on production, processing and body shape traits in market-weight channel catfish, Ictalurus punctatus (Rafinesque)

The effects of feed restriction on channel catfish production, processing yield (carcass and fillet), visceral composition and body shape traits were determined. Channel catfish (initial mean weight =0.77 kg) were stocked into six 0.04‐ha ponds at ～5775 kg ha^?1. Two ponds were assigned to each of three feeding regimes for a 4‐week trial: fed daily to satiation, fed once weekly to satiation and not fed. Fish were measured for weight, processing yield and visceral components after 2 and 4 weeks, and for body shape after 4 weeks. Growth was fastest in fish fed daily, intermediate in fish fed weekly and slowest in unfed fish. There were no differences in survival among feeding regimes. After covariate adjustment for weight differences, fish fed daily had shorter, thicker bodies, and smaller heads than fish from feed‐restricted treatments. Carcass yield was higher for females than males and higher at week 2 than at week 4, but was not affected by feeding regime. Fillet yield was higher for females than males, higher at week 2 than at week 4, and higher for fish fed daily than for feed‐restricted fish (fed once weekly and not fed). Viscerosomatic index (VSI), visceral fat‐somatic index (VFI) and hepatosomatic index were higher at week 2 than at week 4, and highest for fish fed daily, intermediate for fish fed weekly and lowest for unfed fish. Hepatosomatic index and VSI were higher for females than males, but VFI was not different between genders. The female gonadosomatic index increased over time but was not affected by feeding regime. Short‐term feed restriction had negative impacts on growth and fillet yield. Processors could benefit by marketing severely feed‐restricted channel catfish as carcasses rather than fillets since fillet yield declined but carcass yield was unchanged by feed restriction.     

斑点叉尾趋化因子SCYA126基因及其可变剪接

通过探针杂交筛选斑点叉尾(Ictalurus punctatus)BAC基因组文库,利用引物步移的方法对阳性克隆BAC047 K12进行序列测定,得到2 815 bp的SCYA126基因组序列。序列分析表明,SCYA126基因由2个外显子和1个内含子组成;外显子拼接的序列与SCYA126cDNA序列完全一致,编码92个氨基酸,在N端含有2个相邻的半胱氨酸(CC)和2个不相邻的半胱氨酸,为典型的CC趋化因子亚家族成员;其上游调控序列包含TATA框启动子序列和一些与免疫相关的转录因子结合位点。另外,根据与GenBank接收号为BM029630的EST序列的比较分析,发现SCYA126基因组中的内含子没有被剪接,导致翻译后可能产生N端部分缺失的SCYA126蛋白。在胰脏和肝脏中确认了高表达的包含内含子的mRNA的存在,而且其表达量要明显高于正常剪接的SCYA126mRNA。[中国水产科学,2007,14(1):1-7]     

Growth performance, body composition and plasma thyroid hormone status of channel catfish (Ictalurus punctatus) in response to short-term feed deprivation and refeeding

A 6-week feeding trial was conducted to investigate the effects of short-term feed deprivation on inducing compensatory growth and changes in thyroid hormone levels of channel catfish. Feeding treatments consisted of the following four regimes of 2-week duration: satiate feeding (control), no feed for 3 days then feeding to apparent satiation for the next 11 days, no feed for 5 days then feeding to apparent satiation for 9 days, and no feed for 7 days then feeding to apparent satiation for 7 days. These regimes were repeated three times over the 6-week trial in which 25 channel catfish fingerlings, initially averaging 15 g each, were stocked into each of 12, 38-l glass aquaria supplied with supplemental aeration and flow-through water. Depriving fish of feed had a pronounced effect in that fish lost weight in as little as 3 days. Returning the fish to a satiate feeding regime caused a resumption of growth, equal to control growth only in the case of the 3-day deprived treatment, but all periods of feed deprivation failed to induce a period of catch-up growth adequate to compensate for previously lost weight. Feed efficiency also was not improved by the periods of feed deprivation, and restricting feed in excess of 3 days lowered feed efficiency. Fish condition indices were not altered at the termination of the trial. Muscle lipid, muscle protein and liver protein also were not different among feeding regimes. Liver lipid was elevated in fish deprived of feed for more than 3 days every 2 weeks. Plasma thyroxine (T₄) and triiodothyronine (T₃) were equally depressed by 3 days from the onset of feed deprivation. Both hormones rose significantly within 24 h of realimentation, with the greatest increase observed in animals subjected to the briefest feed deprivation. These results support a role for thyroid hormones in the promotion of growth in channel catfish. Whereas feed deprivation appears to rapidly reduce activity of the hypothalamo-pituitary-thyroid axis, the high correlation observed between T₄ and T₃ in all treatments suggests that peripheral deiodinating systems are capable of rapidly generating T₃ from T₄ upon realimentation. More rapid recovery of thyroid hormone production following realimentation may minimize the effects of feed deprivation on growth and feed efficiency of fish subjected to the 3-day deprivation treatment when compared to longer periods.     

Effects of varying dietary compositions using common feed ingredients on growth and feed efficiency of pond‐raised channel catfish Ictalurus punctatus (Rafinesque)

Two experiments were conducted to evaluate various ingredient combinations in a 28% or 32% protein diet for optimum performance of channel catfish Ictalurus punctatus. All diets contained soybean meal and corn, but with or without cottonseed meal, wheat middlings or fish meal (FM). Channel catfish fingerlings were stocked into 0.04 ha earthen ponds at 18 530 fish ha^?1. Fish were fed one of eight diets once daily to apparent satiation for two growing seasons. Results demonstrated that the dietary ingredient composition used had significant effects on fish performance, but magnitude of differences was relatively small. Overall, diets containing FM resulted in greater weight gain (Experiments 1 and 2) and lower feed conversion ratio (Experiment 1) than fish fed all‐plant diets. However, certain combinations of plant ingredients provided the similar fish growth as some diets containing FM. There were no significant differences in weight gain between fish fed soybean meal–corn or soybean meal–corn–wheat middlings‐based diets with cottonseed meal or FM. The use of wheat middlings in the diet had no significant effects on fish production characteristics.     

Replacing Soybean Meal with Alternative Protein Sources in Diets for Pond‐raised Hybrid Catfish, ♀ Ictalurus punctatus × ♂ Ictalurus furcatus

The present study investigated the replacement of soybean meal with combinations of two or three alternative protein sources in diets for pond‐raised hybrid catfish, ♀ Ictalurus punctatus × ♂ Ictalurus furcatus. Alternative protein sources evaluated included cottonseed meal, distillers dried grains with solubles (DDGS), peanut meal, and porcine meat and bone meal (PMBM). Hybrid catfish fingerlings with a mean initial weight of 35 g/fish were stocked into 25 earthen ponds (0.04 ha) at a density of 14,826 fish/ha. Fish were fed once daily to apparent satiation for 166 d. No significant differences were observed for total diet fed, net yield, weight gain, survival, carcass yield, fillet yield, or fillet proximate composition among dietary treatments. Results show soybean meal may be completely replaced by combinations of cottonseed meal and one or two other alternative protein sources including DDGS, peanut meal, and PMBM in the diet without markedly affecting production and processing characteristics and fillet proximate composition of pond‐raised hybrid catfish. These alternative diets may be used during foodfish production when prices are favorable.     

Nutritional effects of protein source in starter diets for channel catfish (Ictalurus punctatus Rafinesque) in suboptimal water temperature

Intensive tank rearing of channel catfish (Ictalurus punctatus Rafinesque) fry can be successfully accomplished with commonly available ‘salmonid’ starter diets. Ingredient substitution in starter diets is less important from the cost perspective but growth, survival and health of fish are major concerns. Several combinations of fish meals and animal protein substitutes were evaluated in diet formulations for hatchery rearing of catfish fry. Sub‐optimal thermal conditions were used which are characteristic for the north‐central USA where catfish culture is important for stocking purposes and live‐fish markets. A diet formulated on the basis of menhaden fish meal (29.1%), herring fish meal (25.1%) and animal by‐product mixture (16.38%) gave numerically the highest growth rate after 13 weeks of feeding, although growth reductions in fish fed diets exclusively with mehaden meal (77.6%) as protein or substituted with 50% animal by‐product protein were not significant. Instantaneous mortality rates were the highest between weeks 2 and 4 of rearing and increased almost proportionally with the increased fish meal protein substitution. A diet based on menhaden fish meal had the highest concentration of phosphorus and several other essential minerals, but these were not reflected in the mineral composition of the fish body at the termination of feeding. Among activities of digestive enzymes, trypsin was depressed in fish offered diets with 75–100% fish meal protein replacement. A diet superior in terms of fish performance was defined in the present study and it was concluded that the initial feeding can greatly affect physiological status of juvenile channel catfish.     

Growth performance,feed utilization and body composition of advanced nursing Nile tilapia (Oreochromis niloticus) fed diets containing Black Soldier Fly (Hermetia illucens) larvae meal

A 32‐day experiment was conducted to evaluate the effects on the performance, feed utilization efficiency and body composition of a strategic inclusion of Black Soldier Fly larvae meal (MM) in a commercially formulated diet for advance nursing Nile tilapia (Oreochromis niloticus). Four isonitrogenous and isoenergetic diets were commercially formulated and manufactured as a control and three test diets with strategic inclusions of MM inclusions (0, 30, 50 and 80 g/kg) and poultry by‐product meal substituting gradually three conventional expensive feedstuffs: fish meal, fish oil and soybean meal. Fish (5.7 ± 0.5 g/fish) were nursed in a cage‐in‐lake system (Volta Lake, Ghana), under conditions similar to commercial farming practices. Control and experimental diets were fed to triplicate cages by hand to visual satiety, six times per day. Growth performance (final weight; weight gain and SGR), feed utilization efficiency indices (FCR and PER) and feed intake were not significantly different (p ≥ .05) between treatments. Survival was significantly different (p < .05) but more likely explained by the stress related to frequent handling on the smaller fish. Fish whole body composition (dry matter, crude protein, lipid, ash and fibre) was unaffected by the treatment (p ≥ .05), except for the fatty acid compositions which mirrored that of the diets.     

Influence of forage fish and dietary lipid supplements on egg quality and fry production in channel catfish (Ictalurus punctatus) × blue catfish (Ictalurus furcatus) hybridization

Hybrid catfish (channel catfish Ictalurus punctatus × blue catfish Ictalurus furcatus) display characteristics that are favourable to aquaculture production. Low hatch percentages are a principal reason this hybrid is not used widely in the catfish industry. This study was conducted to determine whether additional food source rich in lipids may lead to a higher quality egg production. A 10‐week feed trial was conducted in ponds in Auburn, AL. A total of 219 female Kansas Select channel catfish were stocked into nine ponds, 0.04 ha in size. Three dietary treatments were randomly allocated to the ponds. Diet‐1 was a standard 60 g kg^?1 lipid floating catfish feed. Diet‐2 was the same feed supplemented with forage fish at ～28 kg ha^?1. The third diet was the aforementioned catfish feed topcoated with 20 g kg^?1 lipid [10 g kg^?1 menhaden fish oil, 5 g kg^?1 high docosahexaenoic acid (DHA) oil and 5 g kg^?1 high arachidonic acid oil]. Results indicate that brood fish fed the high lipid diet spawned larger egg masses and had larger eggs both in weight and in diameter, with increased complements of fatty acids such as DHA, eicosapentaenoic acid and total n‐3 fatty acids. The neutral and polar lipid fractions are also presented.     

Comparative study on the utilization of different methionine sources by channel catfish,Ictalurus punctatus (Rafinesque, 1818)

The study was conducted to examine the effects of different methionine (Met) sources on the growth performance of channel catfish (Ictalurus punctatus). Six diets with isonitrogen and isoenergy were formulated as positive control (PC) diet (0.57% Met), negative control (NC) diet (0.42% Met) without or with the addition of crystalline DL‐Met (CM), Met hydroxy analogue (MHA), Met hydroxy analogue calcium salt (MHA‐Ca) and microcapsulated DL‐Met (MM) to obtain the same Met level as PC diet. After 8 weeks feeding trial, channel catfish (76.0 ± 0.3 g) fed MHA‐Ca and MM diets, but not CM and MHA diets, had higher weight gain, lipid productive value, protein productive value and lower feed conversion ratio than those in NC group (P < 0.05) and showed no differences in these indicators with PC group (P > 0.05). Levels of serum total protein and total free amino acid (TFAA) of all groups peaked at the 4th h, and CM group had lower TFAA level than that in MM group at the 6th h after feeding (P < 0.05). In NC group, the activities of liver aspartate aminotransferase and alanine aminotransferase peaked at the 4 h after feeding, and the peaking time in CM group was advanced to the 2nd hour, while in MHA, MHA‐Ca and MM groups, the peaking times were delayed to the 6th hour after feeding. The above results indicated that the supplementation of MHA‐Ca, MM rather than CM, MHA in diets deficient in methionine could improve the growth of channel catfish.     

Effects of dietary arginine supplementation on growth,protein optimization and innate immune response of channel catfish Ictalurus punctatus (Rafinesque 1818)

Juvenile channel catfish Ictalurus punctatus were fed casein–gelatin‐based semi‐purified test diets with graded amounts of arginine (ARG, 0.5%, 1%, 2% and 4% of dry diet) for a 6‐week period, to evaluate the effects of dietary ARG supplementation on performance indicators, levels of plasma ARG, ornithine, citrulline, glutamine and glutamate, as well as selected innate immune parameters. Incremental dietary ARG resulted in significant improvements in weight gain, feed efficiency and protein efficiency ratios, protein retention, protein deposition and arginine deposition. Fish fed the 4% ARG diet had significantly higher values for all performance indicators, although these values were not different from those of fish fed the 2% ARG diet with the exception of protein retention, protein deposition and arginine deposition. Conversely, fish fed the 0.5% ARG diet had significantly lower values for all analysed plasma amino acids. Similarly, both phagocyte superoxide anion production and neutrophil respiratory burst were significantly decreased in fish fed the 0.5% ARG diet. These results demonstrate that the indispensability of dietary ARG is not only related to optimized protein utilization for growth but also its supplementation to fish diets may significantly impact several aspects of the immune system, including phagocyte function and thus improve overall fish health.