Assessment of Compensatory Growth in Channel Catfish Ictalurus punctatus R. and Associated Changes in Body Condition indices

A feeding trial was undertaken to evaluate compensatory growth in channel catfish and to chronicle the changes in body condition associated with the imposed feeding strategy. Four 1200-L circular tanks were each stocked with approximately 600 fingerling channel catfish (mean initial weight 32 g). Two tanks represented control fish which were fed to apparent satiation once daily throughout the trial. The two remaining tanks of fish were unfed for 4 wk and subsequently refed daily to apparent satiation for the following 10 wk in order to elicit a compensatory growth response. Fish fed to apparent satiation during the first 4 wk of the trial had a 41% increase in body weight, while the fasted fish decreased in weight by 20%. During the subsequent refeeding period, previously unfed fish were not able to increase growth rates sufficiently to overcome weight loss imposed by the 4-wk feed restriction. However, after 8 wk of refeeding, total increase in body weight of the previously unfed fish was 179 % of initial weight and similar to that of control fish which gained 231 % of initial weight. Hepatosomatic index (HSI) and condition factor decreased rapidly during the fasting period and increased rapidly to control levels during subsequent refeeding. The intraperitoneal fat (1PF) ratio and muscle ratio responded more slowly to feed restriction with IPF ratio decreasing consistently after 2 wk feed restriction. Muscle ratio showed little effect from the 4-wk period of feed deprivation. It appears that not feeding channel catfish fingerlings for 4 wk is too long to induce a compensatory growth response that is optimal for aquaculture; however, HSI may be the index of choice for detecting when refeeding should begin to maximize compensatory growth.     

Feeding dynamics in fish experiencing cycles of feed deprivation: a comparison of four species

Abstract The temporal dynamics of daily food consumption were examined in individually housed fish that experienced four cycles of 1 week of feed deprivation followed by 2 weeks of feeding to satiation. Four species were compared: European minnows Phoxinus phoxinus: Cyprinidae; three‐spined sticklebacks Gasteosteus aculeatus: Gasterosteidae: gibel carp Carassius auratus gibelio: Cyprinidae; and the longsnout catfish Leiocassis longirostris: Bagridae. The stickleback, carp and catfish showed significant compensatory increases in food intake following deprivation, with the response becoming clearer in successive cycles. The temporal pattern of consumption during the refeeding periods differed between the four species. In sticklebacks, daily intake over a refeeding period initially decreased, but then recovered. In minnows, intake tended to decline over a refeeding period. Gibel carp showed an increase in daily intake on refeeding, but this may have reflected an adverse response to weighing. Over a refeeding period, catfish had a weak tendency to show an initial decline, followed by an increase. These differences are discussed in relation to differences in experimental protocols and biological differences between the species.     

花鲈在短期周期性饥饿下的补偿生长

试验设3个饥饿处理组和1个对照组,研究花鲈在短期周期性饥饿下的补偿生长。试验结果表明,不同饥饿处理下的花鲈具有部分补偿生长能力,再投喂下的干物质摄食率(FR)显著高于对照组(P<0.0001),但饲料效率(FE)与对照组相比差异不显著(P<0.05),表明花鲈在短期周期性饥饿下的补偿生长通过提高摄食率实现。花鲈在补偿生长期间的生长效率大幅度提高,在投喂时间为对照组50%的条件下,周期性饥饿7 d(SR77)和周期性饥饿2 d(SR22)组平均特定生长率达到对照组的70.0%。     

Effect of Restricted Feeding Regimes on Compensatory Growth and Body Composition of Red Sea Bream, Pagrus major

Compensatory growth of red sea bream, Pagrus major, during feed deprivation and after refeeding was investigated. Groups of three fish each were allocated into 28 cages. Fish were fed by a commercial feed to satiation twice a day. Four feeding groups of fish were prepared: one group with continuous feeding (C) for 9 wk and three other groups with feed deprivation for 1 wk (F1) in Week 3, 2 wk (F2) from Week 2 to Week 3, and 3 wk (F3) from Week 1 to Week 3, respectively. All fish in the feed deprivation treatments resumed feeding in Week 4. The full compensatory growth was achieved in F1 and F2 fish after refeeding for the first 3 wk but in F3 fish after refeeding for the second 3 wk. Specific growth rate and feed conversion efficiency in all fish experiencing fasting were higher than those of control fish after first 3 wk of refeeding. At the end of feed deprivation in Week 3, crude protein, crude lipid, and energy content of all fish experiencing fasting were lower than those of the control fish. These results indicated that red sea bream experienced 1‐, 2‐, and 3‐wk fasting could achieve full compensatory growth in the 9‐wk feeding trial.     

Effects of cyclic feeding on compensatory growth of hybrid striped bass (Morone chrysops×M. saxitilis) foodfish and water quality in production ponds

An 18‐week study was conducted in 12, 0.1 ha ponds to evaluate the impacts of cyclic feeding regimes on hybrid striped bass (HSB) foodfish production and pond water quality. Approximately 840 HSB [mean weight (std.); 91.08 g (8.18)] were stocked into each pond (8400 fish ha^?1; 3360 fish acre^?1) and fed according to one of three feeding regimes. The three feeding regimes included a control (fed twice daily to apparent satiation), and cycles of 3 weeks feed deprivation followed by 3 or 6 weeks of feeding to apparent satiation (3/3 and 3/6 respectively). Compensatory growth (CG) was observed in both cyclic feeding treatments; however, the response was insufficient for the fish to completely regain lost weight. Final mean weight of control fish (477.9 g) exceeded (P<0.05) that of fish receiving the two cyclic treatments: 3/6 (404.7 g) and 3/3 (353.8 g). Specific growth rate (SGR) of fish in the 3/3 treatment increased during all three refeeding periods, and was significantly greater than controls during weeks 9–12 and weeks 15–18, which represent the refeeding phase of the second and third feeding cycles. Specific growth rate for fish in the 3/6 treatment was significantly higher than controls only during the first 3 weeks of the first feeding cycle. Hepatosomatic index and condition factor were highly responsive measures that closely followed the metabolic state of fish on the feeding cycle. Of the water quality variables measured, total phosphorus was 32% lower in ponds receiving cyclic feeding versus control ponds. Soluble reactive phosphorus was 41% and 24% lower in ponds offered the 3/3 and 3/6 cyclic feeding treatments, respectively, although, significant differences (P<0.10) were only observed between control and 3/3 treatment ponds. Overall, CG was observed in HSB foodfish grown in ponds, although 3 weeks of feed deprivation was excessive and did not allow for complete growth compensation. Weight loss during feed deprivation was influenced by pond water temperatures. Early season feed deprivation did not cause as much weight loss as during the second cycle later in the season. Further studies on shorter deprivation periods applied during moderate to low water temperatures are needed to identify feeding regimes that minimize weight loss and result in a complete CG response.     

Cyclical feed deprivation and refeeding fails to enhance compensatory growth in Nile tilapia, Oreochromis niloticus L.

A 12-week experiment was carried out to evaluate compensatory growth of 6.6 g Nile tilapia Oreochromis niloticus L. under three cyclical regimes of feed deprivation and refeeding. The deprivation and refeeding regimes included four cycles of 1 week of deprivation and 2 weeks of refeeding (S1F2), two cycles of 2 weeks of deprivation and 4 weeks of refeeding (S2F4) and one cycle of 4 weeks of deprivation and 8 weeks of refeeding (S4F8). A group of fish fed to satiation twice daily throughout the experiment served as control. At the end of the refeeding periods, fish deprived and refed cyclically had higher feed intake and specific growth rates (SGR), but lower body weight, than that of the control fish. There was no significant difference in feed efficiency ratio (FER) between the control and fish subjected to feed deprivation during the refeeding periods, and nitrogen retention efficiency (NRE) was not different between any two treatments throughout the experiment. At the end of the experiment, fish subjected to feed deprivation had lower body weight but similar body composition, relative to those of the control fish. No significant differences were found in final body weight, NRE and body composition between the fish subjected to different cycles of deprivation and refeeding, but the fish subjected to one cycle of deprivation and refeeding exhibited high mortality. Our results indicate that partial growth compensation induced by various cycles of feed deprivation and refeeding does not confer a huge advantage in terms of enhancing the production efficiency and reducing the nitrogen waste output in Nile tilapia farming 29–30 °C.     

Cichlasoma dimerus responds to refeeding with a partial compensatory growth associated with an increment of the feed conversion efficiency and a rapid recovery of GH/IGFs axis

Many fish species display compensatory growth (CG), a phenomenon by which fasted fish grow faster during refeeding. However, most studies use a group‐housed fish approach that could be problematic in social fish when interaction between individuals is not considered or eliminated. Additionally, the growth hormone (GH)/insulin‐like growth factors’ (IGF‐1 and IGF‐2) axis is implicated in postnatal growth in vertebrates, but its relevance in CG is not fully understood. Thus, the aim of this work was to determine whether CG occurs in a social fish, Cichlasoma dimerus, using an individually held fish approach and secondly, to evaluate the GH/IGFs expression profile during refeeding by 3 days and 3 weeks. C. dimerus showed partial CG. The feed conversion efficiency (FCE) was higher in three‐day‐refed fish, which presented higher GH plasma and mRNA levels than controls but shown no differences in liver and muscle GH receptors (GHR1 and GHR2) and IGFs mRNA levels. Surprisingly, three‐week‐refed fish exhibited GHR1 and IGF‐2 increments, but a reduction in GHR2 expression in muscle. These results show a strong association between GH levels, growth rate and FCE during refeeding, and a long‐lasting effect of refeeding on muscular expression of GHRs and IGF‐2.     

Compensatory Growth of Juvenile Flounder Paralichthys olivaceus L. and Changes in Biochemical Composition and Body Condition Indices during Starvation and after Refeeding in Winter Season

Compensatory growth and changes in biochemical composition, hematocrit and body condition indices of juvenile flounder Paralichthys olivaceus were assessed during starvation and after refeeding. Twenty juvenile fish were stocked into each 200‐L flow‐through tank to give five treatments with three replicates per treatment: control group fish (C) were hand fed to apparent satiation twice daily for 8 wk, whereas the Sl, S2, S3, and S4 fish were hand fed to apparent satiation twice daily for 7, 6, 5, and 4 wk after 1, 2, 3, and 4 wk of starvation, respectively. During starvation, weight decreased linearly with periods of feed deprivation up to 3 wk. Survival was not significantly different among treatments. At the end of the feeding trial, weight gain (g/fish) and specific growth rate (SGR) of flounder in S2 was significantly (P < 0.05) higher than those of fish in S3 or S4, but not significantly different from those of fish in C or Sl. Feed consumption of flounder (g/fish) was proportional to duration of feeding except for that of fish in S2. Feed efficiency ratio (FER) and protein efficiency ratio (PER) values for flounder in S2 were significantly (P < 0.05) higher than those for fish in C, but not significantly different from those for fish in Sl, S3, or S4. During starvation, hepatosomatic index (HSI) and lipid content of flounder without liver decreased with periods of feed deprivation. However, HSI and condition factor (CF) for flounder in S2 were significantly (P < 0.05) higher than those for fish in Sl, S3, S4 and C except for CF in Sl at the end of the feeding trial. Proximate composition of flounder without the liver was not significantly different among treatments at the end of the feeding trial. In considering above results, juvenile flounder achieved compensatory growth with up to 2‐wk feed deprivation. Compensatory growth of flounder fed for 6 wk after 2‐wk feed deprivation was well supported by improvement in SGR, FER, and PER. HSI could be a good index to monitor changes in body condition during starvation and after refeeding.     

Compensatory growth,feed intake and body composition of Labeo rohita fingerlings following feed deprivation

Ten‐week study was performed on Labeo rohita fingerlings (av. wt. 3.75 ± 0.06 g) to investigate the nature of compensatory growth. Fingerlings were deprived of food for 0 (control), 1 (D1), 2 (D2) or 3 (D3) weeks and refed to satiation for 5 weeks. The feed deprivation was carried out in D3 group on week 3, 4 and 5; D2 group on week 4 and 5; D1 group on week 5, and refeeding of all the groups were started from week 6 onwards. The D1 and D2 groups caught up in body weight with that of control fish within 2 weeks and 4 weeks of refeeding, respectively, but the D3 group had significantly (P < 0.05) lower body weight than the control after 5 weeks of refeeding. Higher growth efficiency was observed in all the feed deprived groups in the 1st week of refeeding only. Feed intake in D1 group became similar with the control after 5 weeks of refeeding, but the D2 and D3 groups were still hyperphagic when the experiment terminated. Thus, compensatory growth was due to hyperphagia and improved growth efficiency. In conclusion, complete compensatory growth was observed in L. rohita fingerlings after feed deprivation of 1 and 2 weeks.     

Effects of Periodic Feed Deprivation on Growth, Feed Efficiency, Processing Yield, and Body Composition of Channel Catfish Ictalurus punctatus

Two studies were conducted in 110‐L flow‐through aquaria and 0.4‐ha ponds to evaluate effects of periodic feed deprivation on the growth performance of channel catfish Ictalurus punctatus. Fish were deprived of feed 0, 1, 2, or 3 consecutive d/wk, l d per 5‐d period, or 3 consecutive d per 10‐d period and fed to satiation on days fish were fed. In Experiment 1, fish fed less frequently than daily consumed significantly less feed (over the experimental period) and gained significantly less weight than fish fed daily, except that feed consumption of fish deprived of feed 1 d/wk was not significantly different from that of fish fed daily. Compared with fish fed daily, fish deprived of feed 2 d/wk had significantly lower feed conversion ratio (FCR). Visceral fat of fish deprived of feed 1 or 2 d/wk was similar to that of fish fed daily, but fish deprived of feed for longer periods had significantly lower visceral fat than fish fed daily. Regression analysis indicated that feed consumption, weight gain, and visceral fat increased linearly as the number of days that fish were fed increased. In Experiment 2, there were no significant differences in the amount of feed fed between fish deprived of feed 1 d/wk and those fed daily. Net production of fish deprived of feed 1 or 2 d/wk or 1 d per 5‐d period was not significantly different from that of fish fed daily, but fish deprived of feed for longer periods had significantly lower net production than fish fed daily. Visceral fat of fish deprived of feed 1 d/wk or 1 d per 5‐d period was similar to that of fish fed daily, but fish on other treatments had significantly lower visceral fat than fish fed daily. Regression analysis showed that as the number of days fed increased the amount of feed fed and net production increased quadratically. Feed conversion ratio, carcass yield, visceral fat, and fillet fat increased, while fillet moisture decreased linearly as the number of days fed increased. Although feeding less frequently than daily may improve feed efficiency, and fish deprived of feed may demonstrate compensatory growth when a full feeding regime is resumed, it may be difficult to provide enough feed to satiate all size‐classes of fish under a multiple‐batch cropping system without causing water quality problems. Under normal economic conditions, fish should be fed daily to apparent satiation without waste and without causing water quality problems. However, during periods of unfavorable economic conditions, channel catfish raised from advanced fingerlings to market size may be fed less frequently than daily to reduce production cost. Results from the present study indicated that feeding channel catfish to satiation 5 or 6 d/wk (not feeding on one or two weekend days) could provide some benefits in reducing production cost through reduced feed and labor costs for food‐sized channel catfish during periods of low fish prices and high feed prices.     

Effects of Feeding Time and Frequency on Growth of Channel Catfish Ictalurus punctatus in Closed Recirculating Raceway Systems

Abstract.– Experiments were conducted to evaluate the effects of feeding time and frequency on the growth, survival, feed conversion, and body composition of channel catfish Ictalurus punctatus cultured in closed recirculating raceway systems. In separate experiments, two stocking sizes (18 and 232 g/fish) of channel catfish were examined. Treatments consisted of 1) feeding catfish once daily, 3% of body weight at 0800 h; 2) feeding catfish once daily, 3% of body weight at 1200 h; 3) feeding catfish once daily, 3% of body weight at 1700 h; and 4) feeding catfish three times daily, 1% of body weight at 0800 h, 1200 h, and 1700 h. Weight gain, specific growth, feed conversion, percentage survival, and fillet proximate composition of channel catfish among treatments did not differ ( P > 0.05). The percentage visceral fat of channel catfish fed the single meal at 0800 h was significantly lower (P < 0.05) than channel catfish receiving multiple feedings, but was not different than the visceral fat content of channel catfish fed at 1200 h and 1700 h. Under the conditions of this study, results indicate neither feeding time or feeding frequency significantly influences the growth, survival, and body composition of channel catfish raised in closed recirculating raceway systems.     

Differences in Growth and Nutrient Efficiency Between and Within Two Channel Catfish Ictalurus punctatus Strains

A 6-wk growth study was conducted comparing fingerling (mean weight = 24.7 g) USDA103 strain channel catfish Ictalurus punctatus to Norris strain channel catfish in an effort to determine strain differences in growth and nutrient efficiency. Variability within strains also was assessed by randomly selecting four families from each strain for comparison. On average, USDA103 fish gained significantly ( P < 0.05) more weight (51.2 vs. 31.7 g) and length (4.7 vs. 4.1 cm) compared to Norris strain catfish. Significantly ( P < 0.05) greater feed consumption (56.6 vs 41.3 g) and feed efficiency (95.7 vs. 89.9) for USDA103 catfish were also observed. Family differences in weight and length gain and feed intake were significant ( P < 0.05) among USDA103 families; whereas, only differences in feed intake and feed efficiency were significant ( P < 0.05) among Norris families. Nitrogen retention was higher ( P < 0.05) for the Norris strain catfish (35.6%) relative to the USDA103 strain average (31.0%). The results of this study reiterate the superior growth and feed efficiency of the USDA103 strain of channel catfish. Observed differences among USDA103 families suggest that further improvements in weight gain can be made through selective breeding; however, improvements in feed and protein efficiency may be difficult.     

Alteration in expression of atrogenes and IGF-1 induced by fasting in Nile tilapia Oreochromis niloticus juveniles

The growth rate of farmed fish is an important factor regarding aquaculture success. An understanding of the cellular events that occur in skeletal muscle when fish undergo periods of fasting and refeeding provides information useful in developing alternative feeding strategies for improving muscle growth in commercially cultivated species. To evaluate the effect of 1–3 weeks of fasting and 10 weeks of refeeding in Nile tilapia juveniles, we analyzed the growth performance and changes in muscle cellularity and the expression of the following growth and muscle related genes: MyoD, myogenin, IGF-1, IGF-1 receptor, MuRF-1, atrogin-1 and myostatin. Reduced body mass was observed in all three groups of fasted fish during their time off feed, and 10 weeks of refeeding resulted in partial compensatory growth of body mass. No differences in the frequency of white muscle fiber diameters were observed between fasted and fed control fish treatments. However, changes in gene expression induced by fasting and refeeding were found. IGF-1 receptor, ubiquitin ligases MuRF1 and atrogin-1 expression increased during the 1–3 weeks of fasting, while IGF-1 levels dropped significantly (P < 0.001) compared to the control treatment. Furthermore, myogenin mRNA level in fish submitted to 3 weeks of fasting was higher in comparison to the control treatment (P < 0.05). Overall, our results showed that 1–3 weeks of fasting can induce muscle atrophy activation in Nile tilapia juveniles, and 10 weeks of refeeding is enough to induce only partial compensatory growth.     

Compensatory Growth of Pond-reared Hybrid Striped Bass, Morone chrysops × Morone saxatilis, Fingerlings

Compensatory growth (CG) or “catch‐up growth” is a period of super‐accelerated growth following a period of suboptimal conditions (i.e., lack of prey availability or overwintering). Little is known about the CG response in pond‐raised fish and whether hybrid striped bass (HSB), Morone chrysops × Morone saxatilis, might exhibit the rapid growth states or improvements in other production characteristics that may accompany the response. To evaluate the potential for CG in HSB culture, a 16‐wk growth trial in twelve 0.1‐ha earthen ponds was conducted. Approximately 2850 fish (mean weight ± SD = 3.2 g ± 1.1) were stocked into ponds and subjected to one of four cyclic feeding regimens. Treatment regimens included a control (0 wk, fed twice daily to apparent satiation) and cycles of 1, 2, or 4 wk of feed deprivation, followed by 1, 2, or 4 wk of feeding to apparent satiation. Fish in the 4‐wk feeding regimen were offered feed twice during the feed‐deprivation period (once every other week). Growth, specific growth rate (SGR), hepatosomatic index (HSI), intraperitoneal fat ratio, and condition factor (CF) were measured every other week, while overall growth, feed efficiency (FE) (FE = [weight gain/feed fed] × 100), and survival were calculated at the trial termination. The effect of these feeding regimens on water quality was examined by monitoring pH, turbidity, total ammonia nitrogen, nitrite–nitrogen, nitrate–nitrogen, soluble reactive phosphorus, and chlorophyll a weekly; total nitrogen and phosphorous biweekly; and dissolved oxygen and temperature twice daily. Cyclic feeding elicited CG; fish subjected to the 2‐wk regimen had a significantly higher SGR than 0‐wk controls during all but the final refeeding period. FE was higher for all fish in the cyclic regimens, although only FE for fish in the 2‐wk regimen was statistically greater (40%) than the controls. HSI was the most responsive measure and significantly decreased in the 2‐ and 4‐wk treatments during feed‐deprivation period and overcompensated during the refeeding period. CF also varied with feeding cycle and proved to be an effective nonlethal measure of predicting a CG response. No statistical differences in water quality parameters were observed. These data suggest that CG can be effectively induced in pond‐raised HSB and that the increase in FE warrants further research for practical application. Future pond studies with fingerling HSB fish should be conducted with emphasis on feed‐deprivation periods of 2 wk and refeeding periods of at least twice that of the feed‐deprivation period.     

Effects of feed restriction on compensatory growth performance of Indian major carps in a carp–prawn polyculture system: a response to growth depression

Effects of feed restriction on compensatory growth (CG) performance of Indian major carps, sediment loading and water productivity in a carp–prawn grow‐out production system were examined. The overall growth and crop performance were in the similar line in both T₁ (regular feeding, 2 times a day) and T₂ (4‐week feeding followed by 2‐week no feed). However, between T₁ and T₃ (8‐week feeding followed by 2‐week no feed), there was a significant (P < 0.05) variation in the overall growth and crop performance. This was probably due to the longer refeeding periods after cyclic food deprivation that successfully triggered compensatory growth response in T₃ (CG Index: 98–104%). Treatment‐wise sediment load ranged between 59.2 and 69.6 m³ t^?1 biomass. Higher the apparent feed conversion ratios, higher was the sedimentation rate. Higher the feed input, higher were the water exchange requirement, total water use and consumptive water use index. Cyclic food deprivation and refeeding also helped in maintaining water quality due to the restricted feed input (10.5% in T₂ and 2.0% in T₃), thus minimizes the input cost and improves production efficiency. Keeping the growth and yield performance, water productivity and economic efficiency in view, T₃ is considered the best feed management protocol followed by T₂ and T₁.     

Evaluation of Plant and Animal Source Proteins for Replacement of Fish Meal in Practical Diets for the Largemouth Bass Micropterus salmoides

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.     

Evaluation of mixed feeding schedules with respect to compensatory growth and body composition in African catfish Clarias gariepinus

An 8‐week feeding trial was conducted in a recycling water system at 28 ± 1 °C to investigate compensatory growth and body composition in African catfish Clarias gariepinus (13.05 ± 0.05 g). A fishmeal‐based diet containing 350 g kg^?1 protein and 17.5 kJ g^?1 gross energy was fed to triplicate groups of 20 fish (per 30‐L tank). Fish were fed the diet either to satiation or feed restricted in six feeding schedules as satiation 56 days; restricted 28 days + satiation 28 days; restricted 14 days + satiation 14 days; restricted 7 days +satiation 7 days; restricted 3 days + satiation 4 days; and restricted 2 days + satiation 2 days. The restricted regime was achieved by offering fish 1% (maintenance ration) of their body weight per day adjusted after fortnightly weighing. African catfish showed partial compensatory growth under alternating periods of feed restriction and satiation feeding with significantly different values (P < 0.05) from fish fed in satiation throughout. However, significantly indifferent (P > 0.05) values of feed, protein, lipid and energy utilization were found under alternating periods of feed restriction and satiation feeding. Significantly higher (P < 0.05) feed intake was observed in treatment with satiation throughout than those in other treatments. All the feeding schedules showed no significant differences (P > 0.05) on body composition, organ indices, eviscerated carcass composition, viscera lipid and liver lipid. These studies reveals that C. gariepinus showed partial compensatory growth responses at alternating periods of restricted and satiation feeding.     

Effect of Dietary Protein Concentration and Feeding Rate on Weight Gain,Feed Efficiency,and Body Composition of Pond-Raised Channel Catfish Ictalurus punctatus1

Two experiments were conducted in earthen ponds to evaluate the effect of dietary protein concentration and feeding rate on weight gain, feed efficiency, and body composition of channel catfish. In Experiment 1, two dietary protein concentrations (28% or 32%) and four feeding rates (≤ 90. ≤ 112, ≤ 135 kg/ha per d, or satiation) were used in a factorial arrangement. Channel catfish Ictalurus punctatus fingerlings (average size: 27 g/fish) were stocked into 0.04-ha ponds at a rate of 24,700 fish/ha. Fish were fed once daily at the predetermined maximum feeding rates for 282 d (two growing seasons). In Experiment 2, three dietary protein concentrations (24, 28, or 32%) and two feeding rates (≤ 135 kg/ha per d or satiation) were used. Channel catfish (average size: 373 g/fish) were stocked into 0.04-ha ponds at a rate of 17,300 fish/ha. Fish were fed once daily for 155 d. In both experiments, five ponds were used for each dietary treatment. Results from Experiment 1 showed no differences in total feed fed, feed consumption per fish, weight gain, feed conversion ratio (FCR), or survival between fish fed diets containing 28% and 32% protein diets. As maximum feeding rate increased, total feed fed, feed consumption per fish, and weight gain increased. There were no differences in total feed fed, feed consumption per fish, or weight gain between fish fed at ≤ 135 kg/ha per d and those fed to satiation. Fish fed the 28% protein diet had a lower percentage carcass dressout and higher percentage visceral fat than fish fed the 32% protein diet. Dietary protein concentrations of 28% or 32% had no effect on fillet protein, fat, moisture, and ash. Feeding rate did not affect FCR, survival, percentage carcass dressout, or fillet composition, except fillet fat. As feeding rate increased, percentage visceral fat increased. Fish fed at ≤ 90 kg/ha per d had a lower percentage fillet fat than fish fed at higher feeding rates. In Experiment 2, dietary protein concentration or maximum feeding rate did not affect total feed fed, feed consumption per fish, weight gain, FCR, or survival of channel catfish. Feeding rate had no effect on percentage carcass dressout and visceral fat, or fillet composition. This was due to the similar feed consumption by the fish fed at the two feeding rates. Fish fed the 24% protein diet had lower carcass dressout, higher visceral fat and fillet fat than those fed the 28% or 32% protein diet. Results from the present study indicate that both 28% and 32% protein diets provide satisfactory fish production, dressed yield, and body composition characteristics for pond-raised channel catfish fed a maximum rate of 90 kg/ha per d or ahove.     

Effect of Feeding Frequency on Feed Consumption,Growth, and Feed Efficiency in Aquarium‐reared Norris and NWAC103 Channel Catfish (Ictalurus punctatus)*

Abstract.— A 6‐wk feeding study was conducted to determine the effect of feeding frequency on growth rate of juvenile Norris and NWAC103 channel catfish, Ictalurus punctatus, reared under laboratory conditions. Four replicate groups of Norris and NWAC103 catfish (average weight of 4.0 ± 0.2 g/fish, SEM) were fed to visual satiety at different feeding frequencies (one, two, or three times daily). The percent of total daily food consumed for Norris catfish fed three times daily (0800, 1200, and 1600 h) was 44.4, 27.7, and 27.9%, respectively, while NWAC103 catfish consumed 42.9, 26.7, and 30.4%, respectively. Specific growth rate and feed intake were higher in fish fed three times daily compared to fish fed once and twice daily for both strains. Feed efficiency was reduced in NWAC103 fed three times daily compared to fish fed once or twice, while feed efficiency was similar among the Norris treatments. Gastrointestinal (GI) tract index ([weight of GI tract/weight of fish] × 100) decreased in NWAC103 catfish as feeding frequency increased, while a similar nonsignificant trend was also observed in Norris catfish. The results of this study demonstrate that aquarium‐reared Norris and NWAC103 catfish fed three times a day consume more feed and gain more weight than catfish fed once or twice a day. The observed decrease in the GI index as a result of feeding more frequently demonstrates that the size of the GI tract increases, relative to body weight, when catfish are fed only once a day. Under laboratory conditions, the number of times a day the fish are fed should be considered when trying to maximize growth of NWAC103 and Norris strains of catfish.     

Compensatory Growth of Olive Flounder,Paralichthys olivaceus,Fed the Extruded Pellet with Different Feeding Regimes

This study was performed to determine compensatory growth of juvenile olive flounder fed the extruded pellet (EP) with different feeding regimes. Seven treatments with triplicates of different feeding regimes were prepared; α fish was daily fed for 6 d a week throughout 8 wk (8WF); α fish was starved for 1 wk and then fed for 3 wk twice [(1WS + 3WF) × 2]; β fish was starved for 2 wk and then fed for 6 wk (2WS + 6WF); χ fish was starved for 5 d and then fed for 9 d four times [(5DS + 9DF) × 4]; δ fish was starved for 10 d and then fed for 18 d twice [(10DS + 18DF) × 2]; δ fish was starved for 2 d, fed for 5 d, starved for 3 d, and then fed for 4 d four times [(2DS + 5DF + 3DS + 4DF) × 4]; and φ fish was starved for 4 d, fed for 10 d, starved for 6 d, and then fed for 8 d twice [(4DS + 10DF + 6DS + 8DF) × 2], respectively. Total feeding day was all same, 36 d except for control group (48 d). Weight gain of flounder in the 8WF treatment was higher than that of fish in other treatments. And weight gain of flounder in the 2WS + 6WF treatment was higher than that of fish in the (5DS + 9DF) × 4 and (4DS + 10DF + 6DS + 8DF) × 2 treatments. Feed consumption of flounder in the 8WF treatment was higher than that of fish experienced feed deprivation. Feed efficiency ratio (FER), protein efficiency ratio (PER), and protein retention (PR) were not significantly different among treatments. Chemical composition of the whole body of fish with and without liver, except for moisture content of liver, was not different among treatments. T₃ level of fish in the 8WF and 2WS + 6WF treatments was higher than that of fish in the (5DS + 9DF) × 4 treatment. It can be concluded that juvenile olive flounder achieved better compensatory growth at 6‐wk refeeding after 2‐wk feed deprivation compared with that of fish with different feeding regimes. And T₃ level of fish seemed to partially play an important role in achieving compensatory growth.