Feed Utilization Parameters Research Articles

Effect of soybean meal diets on the growth performance, ammonia excretion rates, gut histology and feed cost of Nile tilapia ( Oreochromis niloticus ) fry

Aquaculture development in Ghana is currently limited by inadequate supply of fingerlings and prohibitive cost of commercial feeds among other challenges. This study tested the feasibility of using low-cost feeds containing soybean meal instead of fishmeal for nursing Nile tilapia (Oreochromis niloticus) fry. Three isonitrogenous (~48% crude protein) and isoenergetic (~17 kJ/g) diets with increasing inclusions of soybean meal as partial replacements for fishmeal were formulated. A commercial fishmeal-based fry feed served as the control diet. Triplicate groups of 225 fish per tank (average initial weight: 2.09 ± 0.14 g) were stocked in a recirculating aquaculture system and fed the experimental diets for 21 days. Afterwards, we investigated the postprandial metabolism, nutrient digestibility, growth and gut histology in Nile tilapia fry. Simple economic analyses were also conducted to assess the cost-effectiveness of the diets used in the feed trial. The dietary inclusions of the soybean meal significantly reduced feed cost by ~43% relative to the control diet. The growth performance and feed utilization parameters did not vary significantly among the different treatments. The soybean diets elicited significant reductions in villi heights and goblet cell numbers, which corresponded with increasing dietary levels of soybean meal. This study confirms the potential of soybean meal as a partial replacement for fishmeal in Nile tilapia fry diets in terms of lower feed costs, fish growth performance, nutrient digestibility and postprandial nitrogenous excretions. The inclusion of soybean, however, affected negatively the gut integrity of the fry.

EFFECT OF DIETARY SUPPLEMENTATION (PREBIOTIC MIXTURES AND PROTEASE ENZYME COMBINATION) ON GROWTH PERFORMANCE AND FEED UTILIZATION OF RED TILAPIA Oreochromis sp. FED WITH DIETS FREE FISHMEAL

The present study was carried out at Mariculture Research Center, Arish University, North Sinai, Egypt. This study aimed to examine the effects of total replacement of fish meal by a combination of prebiotic mixtures and protease enzyme on growth performance and feed utilization parameters of red tilapia. A total of 150 fish were equally distributed in 15 glass aquaria. Ten fingerlings per aquarium were stocked with an average initial weight 7.40±0.05g and an average initial length 7.30±0.24cm. The fish were acclimatized for two weeks at experimental condition. This study was conducted as four treatments with three replicates. The fish were fed a diet containing 30.14±0.08% crude protein and isocaloric 443.11±0.5Kcal/kg twice a day at a rate of 3% of total body weight for 84 days. At the end of experiment body weight, length and whole body composition were calculated to determine growth parameters and feed utilization. There were significant difference P≤0.05 for all results between treatments. The results of growth parameters indicated that T4 was recorded the highest values of most growth parameters. But T3 recorded the highest condition factor. FCR and PER were not significantly differences between all treatments. The highest feed and protein intake were recorded for control group and T4. The highest dry matter and ether extract of whole body composition were recorded for T3. But the best protein value, gross energy, protein and energy retained were recorded for T4. There were no significantly differences P>0.05 at fat and ash retained.

Effects of dietary non-viable Bacillus sp. SJ-10, Lactobacillus plantarum, and their combination on growth, humoral and cellular immunity, and streptococcosis resistance in olive flounder (Paralichthys olivaceus)

Heat-killed (HK) Bacillus sp. SJ-10 (B), HK Lactobacillus plantarum (P), and their combination were dietary supplemented to olive flounder (Paralichthys olivaceus) to quantify the effects on growth, innate immunity, and disease resistance. Four test diets were supplied: a control feed free of HK probiotics, 1 × 108 CFUs g–1 single treatments of each of HK B (HKB) and HK P (HKP), and an equal proportion of (0.5 HKB + 0.5 HKP) × 108 CFUs g–1 (HKB0.5 HKP0.5). At 8 weeks of completion feeding trail, HKB0.5 HKP0.5 significantly (P < .05) improved growth, feed utilization, and nonspecific immune parameters (respiratory burst and superoxide dismutase) compared to the control group. Similarly, serum lysozyme and myeloperoxidase activities were higher in both HKB and HKB0.5HKP0.5 groups. The levels of pro-inflammatory cytokine IL-6 in the liver and IL-1β in the liver, kidney, and spleen were also improved in the treatments, but microvilli length was only increased in HKB0.5HKP0.5. After Streptococcus iniae 1 × 108 CFUs mL−1 challenged; HKB and HKB0.5HKP0.5 had a higher survival than control and HKP. Overall, dietary administration of synergy HK probiotics elevated growth, cellular and humoral immunity, and streptococcosis resistance in olive flounder.

Dietary taurine incorporation to high plant protein-based diets improved growth, biochemical, immunity, and antioxidants biomarkers of African catfish, Clarias gariepinus (B.).

Plant protein (PP) sources are generally used in high levels in fish diets. Mostly, PP sources are deficient in taurine; hence, there is a need for its supplementation to fish fed high PP diets. Therefore, effects of dietary taurine were examined on growth performance, feed utilization, immunity, and antioxidant parameters of African catfish, Clarias gariepinus (B.). Fish (10.3 ± 0.4g) were fed on diets (40% crude protein) containing different taurine levels of 0 (control), 10, 20, 30, or 40g/kg diet for 12weeks. Fish fed a taurine-free diet (the control) with high PP sources showed poor growth as compared with these fed taurine-enriched diets where taurine stimulatory effects were observed on fish growth and feed intake. Feed conversion ratio and fish survival rate were not significantly differed among different treatments. Fish fed taurine-enriched diets showed also higher levels of serum glucose, cholesterol, total protein, albumin, globulin, aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, urea, and creatinine over that fed the control diet. Furthermore, lysozyme and respiratory burst activities as well assuperoxide dismutase and catalase activities were significantly elevated in fish fed taurine-enriched diets (P < 0.05) and their highest levels were observed in fish fed 30g/kg diet. Additionally, taurine deposition in fish muscles was positively correlated with dietary taurine levels (P < 0.05). The present study concludes that taurine is a limiting factor for growth, immunity, and antioxidants responses of African catfish fed high PP-based diets and it should be incorporated in its diets with an optimum level of 20g/kg diet.

Determination of optimum dietary protein level for juvenile walleye pollock, Gadus chalcogrammus Pallas 1811

An 8-week feeding trial was conducted to investigate the effects of dietary protein level on growth performance, feed utilization, body composition, plasma chemistry and antioxidant parameters of juvenile walleye pollock (Gadus chalcogrammus). Two-hundred and forty juvenile pollock, averaging 4.5 g, were randomly distributed between 12 400-L flow-through circular tanks (20 fish per tank). Four experimental diets with increased crude protein levels (40, 45, 50, and 55 %) were formulated, and referred to as the P40, P45, P50, and P55 diets, respectively. Each diet was assigned to three tanks and the fish were hand-fed to satiation twice daily. At the end of feeding trial, weight gain and specific growth rate increased with increasing dietary protein up to 50 %, and then decreased with further increase in dietary protein. The feed intake of the fish fed the lowest protein diet (P40) was greater than those of fish fed the higher protein diets (P45, P50 and P55). The feed efficiency was the lowest in the P40-fed fish. The protein retention tended to increase with dietary protein, from P40 to P45, and then decline when the dietary protein level was further increased to P55. The whole-body composition, except for the crude protein content, was not affected by the dietary protein content. Antioxidant response was also not affected by the dietary protein content. In conclusion, based on a second-order polynomial regression analysis of weight gain, the optimum dietary protein level for juvenile pollock was estimated to be 48.2 %.

Partial replacement of fishmeal with corn gluten meal, pea protein isolate and their mixture in diet of black sea bream ( Acanthopagrus schlegelii ) juveniles: Effects on growth performance, feed utilization and haematological parameters

Corn gluten meal (CGM), pea protein isolate (PPI) and their mixture (CPP, 1:1 ratio) were evaluated as fishmeal (FM) alternatives in black sea bream (Acanthopagrus schlegelii) juveniles (9.02 ± 0.12 g). A FM diet was designed as control, and other six diets had 20% and 40% FM protein replaced by CGM, PPI and CPP, respectively, with the supplementation of crystalline methionine, arginine and lysine. After the 8-week feeding trial, significantly lower weight gain was found in fish fed the 40% CGM diet (p < .05), whereas other treatments had no statistical difference (p > .05). The values of feed efficiency ratio and feed intake, as well as proximate compositions of muscle and whole body, were not significantly influenced in all treatments. Apparent digestibility coefficients (ADCs) of dry matter, crude protein, threonine, valine, methionine, isoleucine, leucine, phenylalanine and lysine were significantly influenced by protein source. Fish fed the 40% CGM diet had significantly higher content of essential amino acid in muscle than that of the 20% PPI diet. Fish fed the 40% CGM diet had significantly lower content of serum cholesterol than other treatments (p < .05). Elevated serum superoxide dismutase activity was found in fish fed the 40% plant protein diets. In conclusion, between 20% and 40% FM protein could be replaced by CGM, while about 40% FM protein derived from PPI and CPP could be applied in black sea bream.

Effects of salinity level on the survival, growth, feed utilization, carcass composition, haematological and serum biochemical changes of juvenile Meagre (Argyrosomus regius) (Asso, 1801) grown in ground saltwater

A study was performed to examine the effects of salinity on water quality, fish performance, carcass composition and haemato-biochemical parameters in juvenile meagre, Argyrosomus regius. Fish (5.0 g) were stocked in fibreglass tanks at four salinity levels: 8‰, 16‰, 24‰ and 32‰, and fed a pelleted diet (47/17 protein/lipid) for 56 days. Results indicated that the growth, feed utilization, carcass composition and haemato-biochemical parameters of meagre gradually improved with the increase in salinity up to 24‰ and then significantly (p ≤ .05) decreased at 32‰. The survival per cent showed a significant decrease when A. regius exposed to 8‰ salinity. An improvement with 32%, 47% and 34.1% of FCR, protein productive value and energy utilization was detected at 24‰ compared with 8‰ salinity respectively. The highest content of protein and the lowest of lipids were recorded in fish carcass at 24‰ compared with the opposite trend at 8‰ salinity. The 24‰ salinity treatment exhibited the highest value of haemoglobin (4.9 g/dl) and the lowest ratio (0.73) of albumin/globulin. The serum total protein, albumin and globulin were significantly higher at 24‰ and 32‰ salinity than those at 8‰ and 16‰ salinity groups. These findings indicate that 24‰ salinity level might be the best for meagre.

5334000-53340000Optimal Salinity for Head-Starting Northern River Terrapins (Batagur baska Gray, 1831).

Simple SummaryNorthern river terrapins can adapt physiologically or behaviorally across a salinity gradient, so that they can move between freshwater habitats and brackish water or estuaries. However, there is no available information on the optimal salinity of this species for supporting captive husbandry programs before release to natural habitat. In the current study, the optimal salinity for the terrapins was investigated to serve the well-being of turtles. At the end of the rearing period, various observed parameters related to growth, feed utilization, and health indicated that optimal salinity for rearing the terrapins is about 4 ppt, while rearing in freshwater (0 ppt) or other brackish (8 and 12 ppt) water conditions had negative effects on some key parameters that reflect well-being. A polynomial regression fit to terrapin weight gain as function of salinity predicts the optimal salinity as 4.35 ppt. Findings from the current study could be directly used in ex situ conservation programs of northern river terrapins before release to natural habitat. Additionally, concurrent conservation and restoration of the wild habitats with preferred salinity is essential for flourishing terrapin population.Northern river terrapins (Batagur baska Gray, 1831) are Asia’s largest turtles living in both freshwater and brackish water. In the current study, the optimal salinity for head-starting programs of this critically endangered species was investigated in order to serve the well-being of turtles before release to natural habitat. Forty-eight terrapins (54.64 ± 0.18 g initial body weight) were randomly distributed to four salinity levels (0, 4, 8, and 12 ppt) and reared for eight weeks, using three replicates with four terrapins each. At the end of rearing trial, growth performance and feed utilization parameters were superior in terrapins reared at 4 ppt, followed by 8 ppt in the rank order of treatments. Negative stress responses were observed in terrapins reared at 12 ppt, as the fecal activity of amylase-to-trypsin ratio was changed significantly, but not that of proteolytic enzymes. The fecal thermal transition properties indicated an abundance of nutrients in the post-absorptive phase for terrapins reared at 4 ppt, followed by the 8 ppt treatment group. The preferred 4 ppt salinity had no negative effects on the health status of the terrapins in terms of carapace elemental composition or hematological parameters. Second-order polynomial regression suggests 4.35 ppt as the optimal salinity for maximal weight gain. Findings from the current study could be directly used in ex situ conservation programs of northern river terrapins before release to natural habitat.

English

In fish farming, nutrition and haematology are critical. The former accounts for 70% production cost and the later determines an excellent health status of fish. Feeding trials were conducted in the laboratory for 12 weeks to evaluate the growth performance and haematological parameters of Clarias gariepinus fed varying levels of Chrysophyllum albidum seed meal (ASASM) as a replacement for maize in diets. The experimental diets were prepared using 0, 25, 50, 75 and 100% C. albidum seed meal to replace maize. The initial weight of the test organism was 28.6 g stocked in rectangular white plastic with 3 replicates for each treatment. The fish juveniles were fed at 5% body weight. In this study, growth performance, feed utilization and haematological parameters were determined. The mean weight gain (MWG), specific growth rate (SGR) and feed conversion ratio (FCR) were significant across the treatments following the direct relationship to inclusion levels (p<0.05). Protein efficiency ratio (PER) and total fish production were all significantly different across the diets (p<0.05). The reductions in PCV and other primary haematological variables (HB, RBC and TWBC) were significant at p<0.05 as the level of inclusion increased. The blood variables showed that the haematopoiesis of the test organism was positively influenced by ASASM; thus impairing blood production. The increase incorporation of African star apple seed meal (ASASM) was stressful to the experimental fish. There is need to further study the phytochemical factors and trials for suitable processing method to justify the targeted economic gains without compromising the health status. Key word: Red blood cell, experimental diets, catfish, feed ingredients, African star apple seed meal (ASASM).

Nutritional evaluation of a short-horned grasshopper\u201a Oxya hyla hyla (Serville) meal as a substitute of fishmeal in the compound diets of rohu, Labeo rohita (Hamilton)

BackgroundAqua feed demand is rising with the growth of intensive aquaculture. Fishmeal is the major conventional protein source of fish feed but its production cannot be increased due to resource limitation. Thus, suitable fishmeal (FM) substitute is a need to sustain the growth of aquaculture. Use of edible insects in animal and fish feed is gaining interest. Grasshoppers are edible insect and contain considerably high percentage of crude proteins and other nutrients. In the present study, the nutritional efficiency of Oxya hyla hyla meal as replacer of FM was evaluated by feeding Labeo rohita fingerlings with seven iso-nitrogenous compounded diets (33% crude protein) where FM was substituted by Oxya meal (OM) at 0%, 17%, 33%, 50%, 67%, 83% and 100% levels in diet 1 (D1) to diet 7 (D7) respectively. Feeding trail was continued for 100 days.ResultsFeeding experiments showed that OM-incorporated diets were acceptable to the fish and feeding on the diets they grew significantly after 100 days feeding trial in wet weight and length. Results revealed that up to 50% replacement of FM (up to diet 4) did not affect the growth performances, condition factor of fish, apparent protein digestibility, nitrogen metabolism, food conversion ratio (FCR) and protein efficiency ratio (PER) with respect to reference diet (D1, without OM). FCR and PER were found inferior in the diets D5, D6 and D7 where more than 50% FM was replaced. Moreover, diets regardless of FM replacement level showed no negative impact on hepato-somatic index, digesto-somatic index, relative length of gut, retention of protein, lipid and ash and on carcass compositions of the fish.ConclusionThe results revealed that the grasshopper species, O. hyla hyla, might be a new protein-rich ingredient for aqua feed formulation and up to 50% replacement of FM by OM did not affect the growth performances, feed utilisation parameters and flesh quality of the fish L. rohita fingerlings. Therefore, this study suggested that OM meal could be incorporated at least as partial substitute of FM in the compounded carp diet.

Effects of dietary supplementation of oligosaccharides on growth performance, gut health and immune response of hybrid catfish (Pangasianodon gigas × Pangasianodon hypophthalmus)

The effects of dietary supplementation of various oligosaccharide types on growth performance, gut health and immune response were investigated in hybrid catfish (Pangasianodon gigas × Pangasianodon hypophthalmus). The fish (5.50 ± 0.04 g initial body weight) were fed for 10 weeks with fish meal-soybean meal-based diets containing 0.6% of xylooligosaccharide (XOS), galactooligosaccharide (GOS), fructooligosaccharide (FOS) or mannanoligosaccharide (MOS), while the control diet was not supplemented. At the end of experiment, growth performance was similar across the five dietary treatments, but some improvements in feed utilization parameters were mainly observed in fish fed with the MOS diet, followed by the diet containing FOS. The preferred treatment improved gut health, as indicated by the activities of digestive enzymes and microvillus length. Positive responses in protein synthesis capacity and protein turnover rate as well as amount of native myosin and actin were also observed, while the carcass proximate composition did not differ across the five dietary treatments. Improved immunological response and survival rate after challenge with Edwardsiella ictaluri was achieved in fish fed with the preferred oligosaccharide type. Overall, these findings indicate that a MOS supplemented diet can improve growth performance, gut health and immune response in juvenile hybrid catfish. This prebiotic could be applied by supplementation in practical diets for this hybrid fish.

Evaluation of live duckweed, Wolffia globosa as an allochthonous feed for Labeo rohita fry during nursery rearing

A 40 days feeding trial with Labeo rohita (rohu) fry was conducted in six outdoor cemented tanks (5m × 4m × 1 m; 6–8 cm soil base) to establish the relative impact of on‐farm grown live Wolffia globosa (a duckweed with crude protein of 28.57%) and a formulated iso‐nitrogenous feed (crude protein 28.37%) on growth performance, survival, health and overall quality of fingerlings. The experimental tanks were dried, limed at 250 kg/ha, filled with ground water and subsequently applied with cow dung (soaked overnight) and mustard oil cake at 1,000 kg/ha and 50 kg/ha respectively. The fry were stocked at 0.3 millions/ha in six prepared tanks, and fed live Wolffia (T1) and formulated feed (T2). Results of the study indicate better performance (p < 0.05) of fry in terms of final mean weight (7.83 g), length (8.82 cm), daily growth index (6.51 g %/day) and survival (89.5%) than those fed on formulated feed. Furthermore, significantly improved (p < 0.05) feed utilization parameters viz. apparent feed conversion ratio (AFCR), apparent protein conversion efficiency (APCE), apparent protein efficiency ratio (APER); haematological parameters viz. total erythrocyte count (TEC), total leucocyte count (TLC), packed cell volume (PCV), plasma glucose and protein of fry were also observed in T1 (live Wolffia). Overall findings from this study hints towards the possible utilization of on‐farm grown live Wolffia as a suitable nutrient source for fry rearing of L. rohita.

Effect of replacement of de-oiled rice bran with sweet potato leaf meal on growth performance, digestive enzyme activity and body composition of Labeo rohita (Hamilton, 1822)

A 60-days feeding experiment was conducted to evaluate the utilisation of sweet potato leaf meal (SPLM) for replacement of de-oiled rice bran (DORB) in the diets of rohu Labeo rohita (Hamilton, 1822) fingerlings. SPLM has good protein content (22.12%) and digestible energy content (11.81 MJ kg-1). Five iso-nitrogenous (30%) and iso-caloric diets (13.5 MJ kg-1) were prepared by replacing DORB with sweet potato leaf meal (SPLM) at 0% (C), 25% (T1), 50% (T2), 75% (T3) and 100% (T4). Each dietary treatment was tested in triplicates with 12 fingerlings per tank, following completely randomised design. The growth performance and feed utilisation parameters viz., weight gain % (WG), specific growth rate (SGR), protein efficiency ratio (PER) and feed conversion ratio (FCR) were not significantly different (p&gt;0.05) among treatments. The digestive enzyme activity remained unaffected except amylase activity, which increased significantly in 50% SPLM replacement group (T2). Chymotrypsin decreased significantly (p&lt;0.05) in the treatment groups. Metabolic enzymes viz., ATPase activity of liver increased significantly (p&lt;0.05) whereas ALP (alkaline phosphatase) activity in the intestine had irregular pattern. The present study indicates that DORB can be completely replaced by SPLM without affecting growth performance and digestive enzyme activity in the diet of L. rohita.

THE IMPACT OF DIFFERENT STOCKING DENESITIES AND DIETARY PROTEIN LEVELS ON THE PERFORMANCE OF AFRICAN CATFISH (Clarias gariepinus) FINGERLINGS

The current experiment was randomly designed as a 3×2 factorial design to investigate the effects of two fixed factor (stocking density &amp; dietary protein level) on growth performance, feed utilization, survival rate and physiological response of African catfish (Clarias gariepinus). Fishes were allotted in 18 concrete (8×3×0.5 m3; L×W×H) tanks at three different stocking density 30, 20 and 10 catfish fingerlings / m3 and fed on two different protein diets (25 and 30%). Each treatment was applied in three replicates. Fishes were fed 2.5% of biomass body weight twice/day. Results showed that growth performance, feed utilization, survival rate and hematological parameters were significantly improved with increased dietary protein level with low stocking density. The sixth treatment (high protein level 30% and lowest stocking density; 10 fish/m3) exhibited the highest growth performance with no mortalities. Based on the results of the current study, it could be recommended to use protein level diet of 30% or more and stocking density of 10 catfish fingerlings/ m3 to obtain high productivity in a short time with consequent decreased cost.Key words: African catfish; Clarias gariepinus; dietary protein; growth parameters; Stocking density

Effect of partial or total replacement of fish meal with Procambarus clarkii by-product meal in Oreochromis niloticus diets

The present study aimed to evaluate the effect of partial or total replacement of fish meal (FM) with Procambarus clarkii by-product meal (PBM) on O. niloticus growth performance, feed utilization and health. Five isonitrogenous (30% protein) experimental diets were formulated and applied to O. niloticus with initial body weight 10.94 g for four months in ceramic ponds. The control group contained 0% of PBM, while D2, D3, D4 and D5 contained 25, 50, 75 and 100% replacement of FM with PBM, respectively. The present study revealed that the protein content of PBM was 33.13% and its amino acids profile fulfilled the requirements of O. niloticus. All analyzed heavy metals of PBM, except arsenic and iron, were in the permissible limits for O. niloticus. Moreover, the growth performance and feed utilization parameters of fish of all treated groups were significantly different than those of the control one, but the best results were recorded in fish fed diets D2 and D3, followed by fish fed diets D3 and D4. Moreover, the histological investigation revealed that the liver showed alterations only in fish fed diet D5, and the kidneys showed alterations in fish fed diets D4 and D5, however, the gills showed alterations in all treated groups.

Effects of juniper berry oil on growth performance and blood parameters in common carp (Cyprinus carpio)

In this study the effects of commercial juniper berry oil (JBO) as a feed additive in diets for common carp (Cyprinus carpio) was investigated in terms of growth performance, feed utilization and blood parameters. The experimental diets were prepared to contain JBO at rate of 0 (JBO-0), 5 (JBO-5) and 10 (JBO-10) ml/kg. Common carps (3.07 ± 0.15 g) were fed with test diets for a period of 60 days in 40-L aquariums of triplicate groups. The feeding experiment revealed that JBO groups showed significantly better growth performance and feed utilization compared with the control group (JBO-0) (p < 0.05). No significant effect was observed on hemoglobin amount, haematocrit ratio and consequential erythrocyte indices (p > 0.05). In the JBO groups, serum cholesterol, triglyceride, glutamic–pyruvic transaminase and alkaline phosphatase levels decreased significantly (p < 0.05). In contrast, the total protein level showed a significant increase, while glucose, albumin and lactate dehydrogenase levels did not present any significant variation (p > 0.05). Therefore, dietary addition of 5 ml/kg JBO promoted fish growth and positively influenced the blood parameters in common carps.

Does graded substitution of soy protein concentrate by an insect meal respond on growth and N-utilization in Nile tilapia (Oreochromis niloticus)?

Besides fishmeal, soybean protein is the most common protein source in aquafeed. However, the sustainability of soybean production is criticized. Due to the rapid development of aquaculture, the increasing demand for high value feed proteins has initiated research into alternative and more sustainable proteins for aquafeeds. In order to evaluate one promising alternative protein source, a growth study (56 days) was conducted with juvenile Nile tilapia (Oreochromis niloticus, 35 g on average) with a partial substitution of soybean protein by a partly defatted insect meal from black soldier fly larvae (Hermetia illucens). Growth performance, feed utilization and dietary protein quality parameters were evaluated based on analysed body protein deposition.A control feed (8% fish meal, 37% soy protein concentrate (SPC)) and three iso-nitrogenous and iso-energetic experimental feeds with 25, 50 or 100% replacement of SPC by partly defatted Hermetia meal (HM) were formulated. All feeds supplied essential amino acids as recommended for Nile tilapia. Growth response and protein utilization were examined in a semi-closed in-door water recirculation system. A comparative slaughter technique was applied to generate N deposition data for protein quality evaluation based on the standardized net protein utilization (NPUstd) according to the “Goettingen approach”. All feeds were very well accepted. Replacement of SPC by HM up to 50% improved feed protein quality and result in similar specific growth rate and feed conversion ratio, respectively. However, a higher inclusion rate of HM tended to impair growth, but not the observed protein quality. In conclusion, the replacement of SPC by partly defatted HM up to a level of 50% had no negative effect on growth performance and improved the dietary protein quality of tilapia feeds under study. Insect protein from Hermetia illucens could be a promising option to make aquafeed formulation more flexible and sustainable.

Effect of diets supplemented with different seaweed extracts on growth performance and digestive enzyme activities of juvenile white shrimp Litopenaeus vannamei

This study evaluated the nutritional potential of three seaweed extracts (Ulva lactuca, Eisenia sp. and Porphyra sp.) as possible ingredients in shrimp feed to improve growth and main digestive enzyme activities. Seaweed extracts were included in replacement of wheat and soybean meal in isoproteic diets (35 ± 0.5%) at three levels of inclusion (5, 10, and 15%) and tested during 28 days in a feeding trial on Litopenaeus vannamei (initial weight 1.15 ± 0.08 g). Growth performance and feed utilisation parameters, in addition to trypsin, chymotrypsin, lipase and amylase activities, were evaluated. An increase of ash content in experimental diets was observed as seaweed extract inclusion level increased (from 7 up to 13.4%). All shrimps fed with seaweed diets significantly improved (p < 0.01) final weight (FW), weight gain (WG), specific growth rate (SGR) and feed intake (FI) in contrast to control diet. In general, Ulva diets presented the best shrimp growth performance, among which inclusion of 15% Ulva extract resulted in significantly higher FW, WG and SGR (p < 0.01) compared to control, Porphyra and Eisenia diets. In the case of chymotrypsin, lipase and amylase enzyme activity, a significant interaction between seaweed type and inclusion level was found (p < 0.01), where in most cases, inclusion level of 5% of all type of seaweed resulted in an increase of the enzyme activities. The use of any of the three proposed seaweed extracts in balanced feed, especially Ulva, is suggested to promote shrimp growth productivity.

Effect of various organic acid supplementation diets on Clarias gariepinus BURCHELL, 1822: Evaluation of growth, survival and feed utilization

Background: The purpose of the current study was to determine the growth status, survival and feed utilization of catfish ( Clarias gariepinus BURCHELL, 1822) fed various organic acid supplementations. Methods: In total, 1600 fish were randomly distributed into 20 tanks and fed different types of diet: A, control diet without organic acid supplementation; B, control diet supplemented with 0.05% formic, acetic, and propionic acid; C, control diet supplemented with 0.1% formic, acetic, and propionic acid; D, control diet supplemented with 0.05% butyric acid; E, control diet supplemented with 0.01% butyric acid. The control diet was a commercial diet, containing 35% crude protein, 8.58% crude fat, and 2.75% fibre. All fish were fed using a satiation method, three times per day for 56 days. At the end of the trial, growth, survival and feed utilization were determined. Water quality parameters during the trial were also measured once a week. Results: Fish fed diet type D had the significantly lowest ( P<0.05) final weight (FW), weight gain (WG), and specific growth rate (SGR) of all diets. Similar FW, WG, and SGR were found for fish fed diets A-C and E. Meanwhile, the feed conversion ratio, feed efficiency, and survival rate of fish were not affected by any types of diet. The water quality parameters were not significantly different between tanks and weeks: dissolved oxygen 6.79-6.81 mg L -1, pH 7.11-7.19, water temperature 28.97-29.32°C, nitrite (NO 2) content 0.48- 0.50 mg L -1, and ammonia (NH 3) content 0.064-0.066 mg L -1. Conclusion: The supplementation of 0.05% butyric acid in the diet of C. gariepinus for 56 days reduced the growth performance of the fish. However, supplementation of an organic acid in the diet of C. gariepinus had no impact on feed utilization, survival, and water quality parameters.

Effect of Dietary Inclusion of Fermented Mucuna pruriens Leaf Meal on Growth and Feed Utilisation of Clarias gariepinus Fingerlings

Feeding trial was conducted in 18 plastic tanks (60 x 45 x 30 cm) to assess the performance of Clarias gariepinus fingerlings fed diets containing fermented Mucuna pruriens leaf meal as an alternative protein source to soya bean meal. Five isonitrogenous (crude protein-40%) diets were formulated containing fermented Mucuna leaf meal (FMLM) at A(100% FMLM), B(75% FMLM), C(50% FMLM), D(25% FMLM) and E(0% FMLM) and were fed at 5% body weight to triplicate groups of 10 fingerlings (initial mean weight ranged from 6.20± 1.96g – 6.80± 1.97 g) of C. gariepinus for a period of twelve (12) weeks. Growth performance and feed utilisation parameters indicate that E(0% FMLM) diet gave the highest weight gain (168.87± 3.97g) but did not significantly (P≥0.05) differ from D(25% FMLM), (161.30±6.12 g), and the lowest weight gain (89.70± 1.96 g) was recorded in A(100% FMLM). Similarly, the highest specific growth rate (3.79±0.03 g) was recorded in E(0% FMLM) followed by D(25% FMLM) (3.74±0.04 g), and the least value (3.10±0.02 g) was obtained in A(100% FMLM). However, feed conversion ratio (FCR), protein efficiency ratio (PER) and gross feed conversion efficiency (GFCE) were not significantly different (P≥0.05) among the dietary treatments. The highest (1.72±0.12) and least (1.50±0.02) FCR were obtained in A(100% FMLM) and E(0% FMLM) respectively. The result from this study indicates that fermented Mucuna leaf meal could replace soya bean meal up to 25% in the diets for C. gariepinus fingerlings without compromising growth and feed utilisation.