Fish Fed Test Diets Research Articles

Replacement of fishmeal with plant protein in the diets of juvenile lumpfish (Cyclopterus lumpus, L. 1758): Effects on digestive enzymes and microscopic structure of the digestive tract

This study investigated the effects of plant protein concentrates on the activity of digestive enzymes and microscopic structure of the intestine of juvenile lumpfish. The experiment was carried out using triplicate groups of lumpfish of 7 g average initial body weight, to 40 g average final weight, after 54 days. Four experimental diets were used; a fishmeal (FM) based control diet and three test diets with the plant protein concentrates; soy protein concentrate (SPC) and pea protein concentrate (PPC) (1:1 ratio) replacing FM in proportions of 25% (PP25), 50% (PP50) and 75% (PP75), respectively. Nested ANOVA showed several significant treatment differences in histomorphometry. Overall, fish fed test diets exhibited several changes such as shorter mucosal fold height (MFH) in the anterior intestine (AI), increased number of goblet cells (GCs) and width of lamina propria (WLP) in distal intestine (DI), compared to control. Principal component analysis (PCA) on histological indices showed that all three treatment groups (i.e. PP25, PP50 and PP75) had significantly altered overall intestinal architecture, compared to the control group. The observed enteritis was negatively related with the condition factor (CF). Regarding enzyme activities fewer changes were observed across diets. Fish fed the PP50 diet exhibited an increased activity of leucine aminopeptidase (LAP) in the pyloric caeca and a decrease on chymotrypsin (CHY) in the mid intestine (MI) compared to the control. Nevertheless, the overall changes captured by PCA on enzymes were associated only with condition factor (CF) and not with the diets. Overall, histological evaluation confirmed that lumpfish intestinal morphometry was significantly altered by plant protein ingredients at 25%, 50% and 75% levels, but replacing of FM up to 50% did not affected the growth and the enzyme activities up to 75% inclusion level.

Effect of replacing soybean meal with water melon (Citrullus lanatus) seed meal on the growth, feed utilization and body composition of Nile tilapia (Oreochromis niloticus)

The nutritive potential of water melon (Citrullus lanatus) seed meal as dietary protein source in the diet of Nile tilapia (Oreochromis niloticus) using growth performance and nutrient utilization were evaluated in a 56 day feeding trial. One hundred and fifty tilapia fingerlings of average weight 6.12±0.05g were acclimatized for a week, weighed and allotted into five dietary treatments; containing 0, 15, 30, 45 and 60% Citrullus lanatus replacement levels with soybean meal respectively. The diets (35% crude protein and 10% lipid) were isonitrogenous and isolipidic. Each treatment was replicated three times with ten fish per replicate. Fish were fed 5% body weight on two equal proportions per day to determine weight gain, percentage weight gain, specific growth rate, food conversion ratio, protein efficiency ratio and net protein utilization. The result from the study indicated that there was no significant (p>0.05) differences in the FCR and PER between the fish fed control diets and the fish fed test diets.

Responses by African catfish ( Clarias gariepinus ) fed diets containing fish visceral meal as fishmeal replacer

The responses (growth, economic performance and physiology) in African catfish (Clarias gariepinus) fed diets containing fish visceral meal as fishmeal replacer were investigated in a 56-day feeding trial. Five experimental diets, formulated using catfish visceral meal to replace fishmeal protein at 0%, 15%, 30%, 45% and 60%, were fed to triplicate fish group (n = 15 fish/replicate; 5.73 ± 0.05 g). The weight gained by fish fed control diet was significantly higher (p < .05) than fish fed test diets. However, no statistical variations (p > .05) existed in the survival, protein productive value, whole body composition, nutrient retention, liver total protein, sodium and calcium ion concentration. The hepatic metabolic (AST, ALT and ALP) and oxidative (SOD and CAT) enzymes activities and glutathione were not significantly different (p > .05) between fish fed test and control diets except fish fed D15T that had statistically higher (p < .05) values of ALT, SOD enzyme activities, glutathione, potassium and chloride ions. Economic performance of feeding diets containing catfish visceral meal to Clarias gariepinus showed that the incidence of cost was significantly lowered (p < .05) among catfish visceral meal fed group resulting into increase in profit index and profit per kg of catfish produced. However, statistically similarity (p > .05) exists with control group up to 30% replacement level.

Histopathological changes in liver and kidney of sharptooth catfish fed on cooked Jatropha curcas seedmeal based diets

Introduction: Histology of the organs of fish species is important in the understanding of the pathological changes related to nutritional sources. This study evaluates the histopathological alteration in the liver and kidney of sharptooth catfish fed diets containing Jatropha curcas seedmeal in a 56-day feeding trial. Methods: Clarias gariepinus fingerlings of average weight 2.61±0.02g were acclimatized for a week, and allotted into five dietary treatments; containing 0, 25, 50, 75 and 100% Jatropha curcas seedmeal replacement levels for soybean meal respectively. Each treatment was replicated three times with fifteen fish per replicate. Fish were fed 5% body weight on two equal proportions per day. Histological assessment was conducted using standard procedure. Results: There were no lesions on the photomicrographs of the kidney of fish exposed to all the dietary treatments while moderate vacuolation of the hepatocytes was observed in the liver of fish fed diet D1-control diet. There were very prominent melanomicrophage centres in the liver of Clarias gariepinus fed test diet D3 with some hepatocytes which appeared vacuolated. The trend of vacuolation of hepatocytes of the liver among some treatments were not dietary related as no visible lesions were seen in the liver of fish fed test diets D2 ; D4 and D5. Significance: This study established that Jatropha curcas based diets exert hepatoprotective effect on the liver of fish fed with the diets.

1H NMR-Based Metabolomics and Lipid Analyses Revealed the Effect of Dietary Replacement of Microbial Extracts or Mussel Meal with Fish Meal to Arctic Charr (Salvelinus alpinus)

The effects of replacing 40% of dietary fish meal (FM) in a reference diet (REF) with either mussel meal (MM), zygomycete fungi (ZYG), extracted baker’s yeast (EY), or non-extracted baker’s yeast (NY) on the lipid and metabolic profile of Arctic charr (Salvelinus alpinus) were investigated. After a 14-week feeding trial, liver and muscle tissues were collected for lipid (lipid content, lipid class, fatty acid composition) and 1H NMR-based metabolomics analyses (aqueous and chloroform phases). Lipid analyses showed that fish fed ZYG diet had lower liver lipid content and thereby 10% higher level of docosahexaenoic acid compared with REF. Metabolomics analyses showed that on the one hand fish fed NY diet affected liver metabolites (2–3 fold higher concentrations of e.g., n,n-dimethylglycine and betaine) compared with REF, while, on the other hand, the muscle metabolic fingerprint was mainly affected by EY. In general, affected metabolites (e.g., alanine, anserine, betaine, hydroxyproline, isoleucine, malonate, n,n-dimethylglycine, proline, succinate, and valine) in fish fed test diets suggested that the test meal ingredients caused mainly a response in muscle metabolism. Fish metabolism was least affected by MM, which suggests that it may be suitable to replace fish meal in Arctic charr diets.

Effect of total replacement of fishmeal by earthworm and Azolla filiculoides meals in the diets of Nile tilapia Oreochromis niloticus (Linnaeus, 1758) reared in concrete tanks

In order to eliminate use of fishmeal in aquafeeds, we evaluated the effect of total replacement of fish meal by a mixture of earthworm (Eisenia foetida) and aquatic fern Azolla filiculoides in the diets of Nile tilapia Oreochromis niloticus (Linnaeus, 1758). The experiment was conducted in O. niloticus fingerlings (initial mean weight = 5.6±0.2 g) for a period of 60 days. Five experimental diets isoproteic (30.4±0.6% protein) comprising control diet A0 and four test diets (A1 to A4) without fish meal were formulated. To satisfy essential amino acids requirements in test diets, the ratios 2:1; 1:1; 1:2; 1:5 between A. filiculoides and earthworm meals were used respectively in total replacement of fish meal. The diets were tested in triplicate. On termination of the experiment, the final mean weights in the test diets (10.79 to 11.94 g) were lower than 14.9 g obtained in group fed control diet (p&lt;0.05). The best growth performance and feed utilisation were obtained in fish fed test diets A1 and A4 (SGR = 1.25 and 1.26% day-1; FCR = 2.37 and 2.31 respectively). Excess of lysine in test diets was found to affect the feed utilisation.

Use of Biochemically Improved Shrimp Industry Waste in Fry Tilapia (Oreochromis Niloticus, Linnaeus 1758) Diets: Effects on Growth Performance and Carcass Composition

To evaluate the nutritional quality of the shrimp by-products four approximately isonitrogenous (32 ± 2% crude protein) diets containing different types of shrimp waste meal were fed to duplicate groups of ten fry with an initial mean weight 1.43 ± 0.22g /fish for forty two (42) days. Fishes fed with diet D had the highest mean weight gain (MWG) and specific growth rate (SGR) and those fed with the control diet A had the lowest MWG and SGR. There were no noticeable change in food conversion ratio (FCR) of the fishes fed with diets B, C and D which are significantly different from the FCR of those that fed with control diet A. The survival of fry tilapia ranged from 70 to 100%, being 70% for D, 80% for B, 90% for C and 100% for A. There were no significant differences in body protein content among the fish fed with diets B, C, D and the initial fish. The lowest body protein was obtained in the fish fed with control diet. The tilapia fed with control diet had the highest body lipid content as compared to the initial fish. However, there were no significant differences in body lipid content among the fish fed test diets B, C and D as compared to the initial fish. The variations in body ash content of initial fish and those fed with test diets were significantly different. The initial fish had the highest body ash content.

Assessment of the feasibility of including high levels of rapeseed meal and peanut meal in diets of juvenile crucian carp (Carassius auratus gibelio♀ × Cyprinus carpio♂): Growth, immunity, intestinal morphology, and microflora

Two experiments were conducted to evaluate the feasibility of including high levels of rapeseed meal (RSM) and peanut meal (PNM) in juvenile crucian carp (Carassius auratus gibelio♀×Cyprinus carpio♂) diets by investigating the growth performance, immunity, intestinal morphology, and microflora of these animals. Fish meal (FM)-based diets were used as controls in both experiments. In experiment 1, RSM and PNM replaced 250 (RSM25 and PNM25) and 500 (RSM50 and PNM50) gkg−1 of FM in test diets. In experiment 2, RSM and PNM substituted 500gkg−1 of FM in test diets (RSM50′ and PNM50′, respectively). The diets in experiment 2 were isonitrogenous and isocaloric, and supplemental crystalline amino acids were added to compensate for the reduction in essential amino acids. More than 100gkg−1 of FM was maintained in the test diets in both experiments to ensure palatability, and fish were fed these diets for 8weeks. No significant changes in feed intake were noticed among groups in both experiments. In experiment 1, the growth rate (GR) of fish fed test diets was significantly lower than in fish fed control diets; the feed conversion ratios (FCR) were higher in fish fed test diets than in fish fed control diets with the exception of fish fed the PNM25 diet. The lower GR observed in fish fed test diets was partly due to reduced dietary energy and protein levels. No significant differences were observed in the GR of fish in experiment 2; however, the FCR of fish fed the RSM50′ diet increased, whereas the protein efficiency ratio decreased in fish of both test groups, suggesting that growth retardation would have occurred over a longer period. No significant changes were observed in serum superoxide dismutase activity in both experiments. Compared with control groups, the lymphocyte proliferation index (LPI) decreased in fish fed the RSM50 diet but not in those fed the RSM50′ diet; the LPI increased in fish fed the PNM50 and PNM50′ diets. The secretion of mucus, which formed a peritrophic membrane-like structure, was enhanced when diets included high levels of RSM and PNM. Mild intestinal histological changes, but no significant inflammatory responses or intestinal microflora changes, were observed. From these results, we came to the general conclusion that the inclusion of high levels of RSM and PNM in the diet not only retarded growth but also produced health risks to the crucian carp.

THE EFFECT OF SUBSTITUTING MAIZE WITH GRADED LEVEL OF BISCUIT WASTE ON THE GROWTH PERFORMANCE, NUTRIENT UTILIZATION, CARCASS COMPOSITION, HAEMATOLOGICAL PARAMETERS AND ECONOMIC PERFORMANCE OF AFRICAN CATFISH Clarias gariepinus (BURCHELL 1822)

The effect of replacing maize with biscuit waste (BW) in the diet of Clarias gariepinus was evaluated in a 70-day feeding trial. Four isonitrogenous diets were prepared in which biscuit waste was used to replace maize at a rate of 50, 75 and 100% respectively. A diet without biscuit waste served as control. Each treatment had three replicates stocked with 10 catfish juveniles per tank with (mean initial body weight16.44±2.21g) per fish. The performance of the fish fed test diets was compared with fish fed a maize-based control diet containing 42.94% crude protein. The fish on the test diets performed better than the fish fed control diet with respect to mean weight gain (95.12±2.78g in BW 75 Vs 78.67±3.74g in control) and specific growth rate (3.04±0.04 %day -1 Vs 2.79±0.07 %day -1 ). Feed intake, feed conversion ratio and the protein efficiency ratio were not significantly different between test diets and the control. The inclusion of biscuit waste significantly improved (P<0.05) crude protein retention in the fish carcass. All the haematological parameters increased as a result of BW inclusion, the converse was however observed in cholesterol and triglyceraldehyde. There was significant difference (P<0.05) in the cost of feed intake and value of fish. Â

Dietary Methionine Requirement for Growth of Juvenile Humpback Grouper (Cromileptes altivelis)

An experiment to find out amino acid methionine requirement for growth of juvenile humpback grouper has been conducted in 18 polycarbonate 100 L tanks. Each tank was equipped with flow-through water system. Twelve juveniles of humpback grouper (5.6 ± 0.7 g each) were randomly selected and stocked in each tank. Juveniles humpback grouper for the experiment were purchased from back yard hatchery in Gondol. Fish fed test diets twice everyday at satiation level for 49 days. Test diets were prepared as dry pellet with casein and fish meal as the intact protein sources, supplemented with the mixture of crystalline L-amino acids to correspond to the amino acid pattern found in the whole body protein of the juvenile humpback grouper, except methionine. Basal diet (diet-1) containing 0.86% methionine was supplied from casein and fish meal. Graded level (0.3%) of L-methionine was added to the basal diet to get the final methionine level in each test diet of 0.86%, 1.16%, 1.46%, 1.76%, 2.06%, and 2.36 %. The experiment was designed according to completely random design (CRD) with 6 treatments (methionine levels) and three replicates for each treatment. Result of the experiment showed that dietary methionine content influenced final weight, weight gain, specific growth rate, feed efficiency, protein retention, and body protein content of juvenile humpback grouper. Optimum dietary methionine for juvenile humpback grouper was calculated using broken line regression analysis. Optimum dietary methionine requirement for growth of juvenile humpback grouper was 1.18% (2.41% of dietary protein) and 1.16% (2.37% of dietary protein) based on weight gain data and feed efficiency, respectively.

Effect of Chinese parsley Coriandrum sativum and chitosan on inhibiting the accumulation of cadmium in cultured rainbow trout Oncorhynchus mykiss

Toxic heavy metals such as cadmium (Cd) accuulate in cultured fish from solid-form feed mixtures. In this paper, two natural ingredients, supposed to inhibit accumulation of heavy metals in the fish body, were investigated to develop a functional feed mixture for healthy fish. Three test diets: (i) #1, regular diet as negative control; (ii) #2, #1 +2% lyophilized Chinese parsley Coriandrum sativum (CP); and (iii) #3, #1 +3% chitosan (CT), were each fed to 50 rainbow trout Oncorhynchus mykiss once a day, at the constantrate of 1.0–1.2% of body weight for 12 weeks. No undesirable effect on fish growth was observed by an addition of either CP or CT to regular feed. Then, 10 mg Cd was added to 1 kg each of the three test diets and they were named as: (i) #4, #1 +Cd; (ii) #5, #2 +Cd; and (iii) #6, #3 +Cd, respectively. The fish given positive a control feed (diet #4) for 3 weeks accumulated Cd in the liver and kidney at approximately 0.52 mg/kg. However, Cd in ordinary muscle was found to be just above the detection limit. Upon accumulation of Cd, three groups of 50 fish were each fed test diets #4, #5, and #6 for 12 weeks at the same feed rate described above. The concentrations of Cd accumulated in the liver, kidney, and ordinary muscle of the fish were measured every 3 weeks. Contrary to the positive control fish fed diet #4, those fish fed test diets #5 and #6 accumulated 20–30% and 25–40% less Cd in the liver, respectively. Test diets were a little less effective for inhibition of Cd uptake in the kidney than that observed in the liver. These results suggest that addition of CP or CT to fish feed might be used to decrease toxic heavy metal accumulation in fish.

Phosphorus retention efficiency in rainbow trout fed diets with low fish meal and alternative protein ingredients

: Two experiments were conducted to evaluate feed quality and body phosphorus (P) and nitrogen (N) retention by rainbow trout fed test diets with low amounts of fish meal content and alternative low-P protein sources. A fish meal (FM) diet was used as control. Fish weighing 2.0 g and 134.7 g on average were reared with the experimental diets for 30 weeks and 15 weeks, respectively. The experimental diets had a good growth rate and feed utilization. In the first experiment the P retention was higher in the group of fish fed test diets (56 and 69%) compared to the FM-based diet (36%); N retention rates were similar for all groups. In the second experiment, fish were fed the test diet that had the best P retention in the earlier experiment. The P retention was lower than the values obtained in the first experiment (smaller fish), but still higher in the group of fish fed the low FM diet in comparison with the control group (36.0% and 22.2%, respectively). This represents a P loading into the water of 5.9 kg/t and 12.8 kg/t production for the test and the control diet, respectively. Therefore, low-P-loading diets for rainbow trout can be developed through the appropriate combination of alternative protein sources.

Dietary vitamin E supplementation affects tissue lipid peroxidation of hybrid tilapia, Oreochromisniloticus× O.aureus

A feeding trial was conducted to evaluate the effects of dietary vitamin E contents on the growth, ascorbate induced iron-catalyzed lipid peroxidation in post-mortem muscle and liver tissue, and Raman spectral changes in lens of juvenile hybrid tilapia ( Oreochromis niloticus× O. aureus). Experimental fish were fed practical diets supplemented with 0, 50, 100, 200, 450 and 700 mg α-tocopheryl acetate/kg diet for 14 weeks. There was no significant difference in weight gain, feed conversion ratio and protein efficiency ratio among fish fed test diets ( P>0.05). Protein content of fish fed diet containing the lowest vitamin E level was the lowest ( P<0.05) among all groups. No difference was found in other body constituents among test fish ( P>0.05). The thiobarbituric acid-reactive substances produced by iron-catalyzed lipid peroxidation in muscle and liver tissue of fish fed the diet without α-tocopheryl acetate supplementation were significantly ( P<0.05) greater than those from fish fed diets containing higher levels of α-tocopheryl acetate. Dietary vitamin E supplementation increased the antioxidant capability of tilapia tissues against lipid peroxidation. Further, dietary vitamin E supplementation also influenced the lens cortical membrane structure of tilapia.

Digestibility of various feedstuffs by post-juvenile chinook salmon ( Oncorhynchus tshawytscha) in sea water. 2. Measurement of digestibility

This study was undertaken to determine the digestibility of organic matter, crude protein, and gross energy, in selected animal and plant feedstuffs using post-juvenile chinook salmon held in running 8–12.5°C filtered sea water (28–31 ppt) on a natural photoperiod. Feces were collected by either a modified Guelph procedure, stripping or intestinal dissection using chromic oxide as the indigestible marker. Most fishmeal sources contained more digestible energy for chinook salmon than did the other test animal and plant protein sources. Two sources of poultry by-product meal differed markedly in percentages of digestible protein and energy. Blood meal, which was dried in a continuous dryer, had very low percentages of available protein and energy. A commercial source of canola meal, one source of glucosinolate-free canola meal and rapeseed protein concentrate were all well digested. The digestibility of commercial sources of soybean meal and soybean protein isolate could not be ascertained accurately because fish fed test diets containing these protein sources exhibited poor appetite. The energy in extruded wheat was absorbed much better than that in wheat middlings. The Guelph system of fecal collection appeared to provide reliable estimates of feedstuff digestibility using chinook salmon in sea water.

Lipids of arctic charr,Salvelinus alpinus (L.) I. Dietary induced changes in lipid class and fatty acid composition

Arctic charr (Salvelinus alpinus L.) were fed either a commercial diet or six experimental test diets containing coconut oil and different polyunsaturated fatty acids (PUFA) at a level of 1% by dry weight. Best growth rates were observed with the commercial diet, worst with diet containing coconut oil with no PUFA. An increase in hepatic lipid, hepatic sterol esters and muscular moisture content, and a decrease in muscular lipid was generally found in fish fed the test diets compared to those maintained on the commercial diet.Phosphatidylcholine was the dominant polar lipid (PL) class in all tissues examined. Extensive modification of dietary saturated fatty acids into 18:1 (n-9) was observed in tissue triacylglycerols (TAG) of fish fed test diets. No changes occurred with the commercial diet.Dietary PUFA were essentially incorporated unchanged into tissue TAG of all fish in the present study. PUFA composition of hepatic phospholipids was significantly influenced by that contained in the diets. However both 18:2 (n-6) and 18:3 (n-3) in the test diets were extensively elongated and desaturated prior to incorporation into PL. The (n-9) PUFA content was always higher in liver of fish fed the test diets. When 18:2 (n-6) and 18:3 (n-3) were supplied together, the level of (n-3) PUFA exceeded those of (n-6) PUFA. Muscle PL were less influenced by diet than liver. In muscle (n-3) PUFA were always the predominant PUFA irrespective of diet. Only low amounts of (n-9) PUFA were found. It is suggested that (n-3) PUFA are the prime essential fatty acids for Arctic charr, and that they are used in preference to (n-6) PUFA for elongation, desaturation and incorporation into PL. The results suggest that the quantitative requirement of Arctic charr for EFA is may be higher than that of other salmonids.