Feed Utilization Indices Research Articles

Dietary lysophospholipid improves growth performance, antioxidant capacity and immunity response of red tilapia (Oreochromis niloticus × O. mossambicus)

Lysophospholipids (LPL) are usually used as emulsifiers in fish nutrition because of their ability to ameliorate nutrient digestibility and lipid metabolism. The present study aims to assess the effects of a commercial dietary lysophospholipid on growth performance, feed utilization, antioxidant activity, innate immunity and biochemical indices of red tilapia (Oreochromis niloticus x O. mosambicus) fingerlings. Five isonitrogenous (35.8% CP) and isocaloric (18.7 MJ kg−1) diets were prepared as follows: two control diets coded as C1 and C2, containing 2 and 1% soybean oil, respectively. The other three diets were coded as LPL1, LPL2 and LPL3, and were formulated by supplementing the C2 diet with 0.1, 0.2 and 0.3% lysophospholipid. The fingerlings of red tilapia (2.13 ± 0.42 g fish−1) were fed the diets for 70 days. The highest significant (p < 0.05) final weight and weight gain were recorded in LPL2. The best values of feed efficiency and protein efficiency (PER)were in all fish groups fed LPL in their diets (p < 0.05). Protein productive value (PPV) showed the highest result in LPL3 (p < 0.05). Lysozyme activity showed the best result in LPL3 (p < 0.05). The highest values of alternative complement activity (ACH50) and total immunoglobulin (Ig) were in LPL3 and LPL2 (p < 0.05). The best results of superoxide dismutase (SOD) and catalase activity were recorded in LPL3 (p < 0.05). The lowest values of triglycerides (TG) and total cholesterol (CHO) were detected in LPL1 and LPL2 (p < 0.05). Thus, the inclusion of 0.2% of the commercial lysophospholipid in red tilapia diets enhanced the growth performance, feed utilization, innate immunity, antioxidant activity and lipase activity, and reduced CHO and TG of red tilapia fingerlings.

Use of bacterial-based single-cell protein MRD-Pro® in diets for Nile tilapia (Oreochromis niloticus) fry

The research assessed the inclusion of MRD-Pro?, a bacterial-derived single-cell protein (SCP), in the diets of Nile tilapia (Oreochromis niloticus) fry with an initial weight of 0.12 grams. Using a diet composed of 45% crude protein and 14% crude fat, with an initial fishmeal content of 8.0% (designated as Diet 0.00% SCP, the control), SCP replaced 50% and 100% of the fishmeal on a protein basis, incorporated at levels of 4.25% and 8.50%, respectively. In addition, two more diets were prepared with higher levels of SCP, 14.50% and 21.00%. All diets were isoproteic and isolipidic. Weight gains of fish fed with the control diet (27.26 g) and the 4.25% SCP diet (21.61 g) were statistically comparable among themselves but were significantly greater than those of fish fed the 8.50% SCP (10.45 g), 14.50% SCP (11.54 g), or 21.00% SCP (7.28 g) diets, a trend observed across all growth and feed utilization indices. Increasing dietary SCP significantly reduced the crude fat and dry matter content in fish muscle tissue, while minimal changes in the amino acid profile of fish muscle tissue were observed. The bacterial-based SCP MRD-Pro? is a nutritious feed additive that can be effectively incorporated, within limits, into the diet of tilapia fry.

Combined Effects of Yellow Mealworm (Tenebrio molitor) and Saccharomyces cerevisiae on the Growth Performance, Feed Utilization Intestinal Health, and Blood Biomarkers of Nile Tilapia (Oreochromis niloticus) Fed Fish Meal-Free Diets.

Aquafeed quality is the most critical factor for aquaculture sustainability. However, limitations of traditional feed ingredients such as fishmeal (FM) need alternative strategies to ensure the nutritional requirements for aquatic animals. In this trial, four test diets were formulated (2 × 2 factorial design), where FM was incorporated in two diets at 10% with or without Saccharomyces cerevisiae (SC) at 1 g/kg. At the same time, FM was replaced with yellow mealworm (Tenebrio molitor) meal (TM) with or without SC at 1 g/kg. The growth performance indices (final weight, weight gain, and SGR), and the feed utilization indices (FCR and PER) were markedly affected by the protein source (FM or TM) and dietary SC (P < 0.05). The protein source (FM or TM) significantly (P < 0.05) affected the whole-body protein and lipid contents, while the moisture and ash contents were unaffected (P > 0.05) by TM or SC. The growth of the intestinal villi showed a marked increase in both height and branching in the treated groups with SC along the whole length of the intestine. Furthermore, the immune cell infiltration was prominent near the intestinal crypts of the middle intestinal segments in the supplemented groups by SC. Dietary TM and SC revealed improved hepatic parenchyma in the liver tissue better than other groups. The hematological indices, including hemoglobulin, hematocrit, red blood cells, and white blood cells, were markedly affected by dietary SC (P < 0.05). The lysozyme activity and phagocytic index were markedly affected by dietary SC, while phagocytic activity was affected by dietary TM (P < 0.05). The catalase, glutathione peroxidase, and malondialdehyde were markedly affected by the interaction between dietary protein source and SC, while superoxide dismutase was affected by dietary SC (P < 0.05). In conclusion, adding SC could enhance the utilization of TM by Nile tilapia with positive effects on the intestinal and liver histological features and the immune and antioxidative responses.

Effects of digestible carbohydrate levels on growth performance, feed utilization, body composition, and biochemical indices of juvenile spotted knifejaw, Oplegnathus punctatus

The effects of digestible carbohydrate levels (0–25 %) on growth, body composition, feed efficiency, and biochemical parameters of juvenile Oplegnathus punctatus (IBW, 12.51 ± 0.02 g) were studied. By adjusting the ratio of corn starch to cellulose, six iso-nitrogenous and iso-lipid diets were formulated. Each diet was divided into three groups (18 fish per replication) for 8 weeks. The results showed that specific growth rate (SGR) and weight gain (WG) were significantly improved (P < 0.05) as digestible carbohydrate levels increased from 0 % to 20 %, but this trend was reversed when the level exceeded 20 %. Correspondingly, feed conversion rate (FCR), protein efficiency ratio (PER), and nitrogen retention (NR) values tended to improved. As digestible carbohydrate levels increased from 0 % to 25 %, daily energy intake (DEI) increased while energy retention (ER) decreased (P < 0.05). Additionally, whole-body crude protein and crude lipid content tended to increase with rising digestible carbohydrate levels. The glycogen content in the liver and muscle increased as digestible carbohydrate levels rose from 0 % to 15 %, while plasma triacylglycerol (TG) concentration decreased as digestible carbohydrate levels increased from 0 % to 20 % (P < 0.05). Compared with other groups, fish fed the C25 diet displayed lower (P < 0.05) amylase activity. Based on the quadratic regression analysis of SGR and WG, dietary digestible carbohydrate levels of 18.31–19.00 % can provide maximum growth for juvenile O. punctatus.

Effects of dietary β-mannanase (Hemicell®) and Lavandula angustifolia on Oreochromis niloticus fed a low level of dietary protein: Growth, digestive enzymes, and hemato-biochemical indices

High feed prices and limited access to feed are two critical problems faced by fish producers. One approach that farmers may consider is using less expensive and locally available components. We conducted a 60-day feeding trial to investigate the consequences of the dietary addition of Hemicell® (HC) as exogenous β-mannanase and lavender flower meal (LFM) in low- protein diet (25 % CP) in Oreochromis niloticus. The investigation assessed growth, feed utilization, somatic, body composition and hemato-biochemical indices, and digestive enzyme activity. Fish (N = 180; average weight: 17.17 ± 0.72 g) were haphazardly organized into six groups in triplicates (10 fish/replicate) and stocked in 18 plastic tanks (60 L). For 60-days, fish groups were fed on six prepared experimental diets. The negative control group (NCG) and positive control group (PCG) were fed basal diets containing 30 % CP and 25 % CP, respectively. Groups (G1-G4) were fed on basal diets containing 25 % CP and supplemented with 0.25 g/kg HC, 0.5 g/kg HC, 0.25 g/kg HC+ 10 g/kg LFM, and 0.5 g/kg HC+ 10 g/kg LFM, respectively. The findings showed decreases in the growth, body composition (crude protein and lipids), and white blood cells count (WBCs) in PCG as compared with the control group (NCG); meanwhile, no significant alteration was recorded for other parameters. Dietary addition of HC alone or with LFM enhanced growth, feed utilization, digestive enzymes activity (trypsin, amylase, and lipase), serum total protein, and hematological indices (red blood cells count, WBCs, and Hb) as compared with PCG. The highest results were notable in G2. No marked impacts were observed on water quality parameters, fish survival, somatic index (hepato-somatic and visceral-somatic), and the level of cholesterol, glucose, and creatinine in fish serum by dietary HC or LFM. However, values of triglycerides, urea, hepatic enzymes (alanine and aminotransferases), and body crude lipids increased by supplementation of HC alone or with LFM. Our findings demonstrated that feeding O. niloticus a low-protein diet supplemented with HC (0.5 g/kg) could promote growth, digestive capability, and health status. This provides a platform for potential exogenous enzyme (HC) use in low-protein diets to reduce feed costs and support the aquaculture industry.

Regulatory roles of Pawpaw (Carica papaya) seed extract on growth performance, sexual maturity, and health status with resistance against bacteria and parasites in Nile tilapia (Oreochromis niloticus)

Papaya (Carica papaya) is one of the plants that represent a major source of bioactive substances that are cheaper and non-toxic, such as antibiotics. It is globally used as a supplement diet for positive effects in pharmacological activities. In this regard, the current study sheds light on the possible roles of papaya seed methanolic extract (PSE) as a dietary supplement to improve growth performance, sexual maturity, carcass composition, immunity responses, histological structure of gonads, and anti-pathogenic activity (Aeromonas hydrophila) at the end of a feeding trial extend for ten days of Nile tilapia, with special reference to its potential effect as resistance against parasitic (Cichlidogyrus tilapiae). Four experimental groups with four replications of Nile tilapia fry (0.5 ± 0.1 g as 20 fish per replication) were fed (0, 0.5, 1.0, and 2.0 g/kg PSE in diets) for 20 weeks. Results showed that fish dietary supplementation with PSE had a significantly positive (P < 0.05) effect on growth performance, feed utilization, digestive enzyme, carcass composition, antioxidant, immunity responses, and hematological and biochemical indices, especially PSE 2.0 g/kg than control diet. Furthermore, PSE had a positively affected fish mortality after injection with A. hydrophila and in vitro positive efficacy against C. tilapiae. Fish fed with dietary PSE increased the sex ratio in favor of male fish by achieving a 77% male phenotype. Conclusively, this study declared that PSE extract, specifically 2 g/kg, could enhance growth and health through the modulation of innate immunity and a positive effect against disease in fish. Additionally, it reduced the reproductive performance of Nile tilapia by reducing GSI, which subsequently affected the gonadal histology leading to infertility.

Evaluation of Different Copper Sources in Nile Tilapia Diets: Growth, Body Indices, Hematological Assay, Plasma Metabolites, Immune, Anti-Oxidative Ability, and Intestinal Morphometric Measurements

The goal of the current study was to compare how well Nile tilapia, Oreochromis niloticus, utilized copper (Cu) as bulk and nano sources by evaluating fish growth, body indices, hematological assays, plasma metabolites, immune and anti-oxidative abilities, and intestinal morphometric measurements. The basal diet served as a control, with no Cu added, whereas the experimental diets were formed by adding bulk-Cu and nano-Cu to the basal diet to keep Cu levels at 3 and 6 mg kg−1, respectively, in both Cu sources. Tilapia (9.10 ± 0.014 g) were fed the control diet and four experimental diets for 12 weeks. Results indicated that growth, feed utilization, and body indices demonstrated a substantial improvement (P ≤ 0.05) in tilapia that received a diet containing 3 and 6 Nano-Cu mg kg−1 diet, compared to the performance of fish that received diets containing 3 and 6 Bulk-Cu mg kg−1 diet and the control diet. Villi height, villi width, absorption area of villous (AAV), and mucosal to serosal amplification ratio (MSR) values demonstrated a substantial increase (P ≤ 0.05) in tilapia fed 3 and 6 mg kg−1 Nano-Cu compared to the values observed in fish fed the control and Bulk-Cu supplemented diets. Fish fed Bulk-Cu recorded the highest (P ≤ 0.05) hemoglobin concentration in those fed 6 mg kg−1 compared to 3 mg kg−1. Hematocrit value considerably improved (P ≤ 0.05) by supplementation of Cu, whereas the highest significant value demonstrated in fish provided 6 mg/kg−1 Nano-Cu. A fish-fed diet containing 3 mg kg−1 Nano-Cu revealed the best (P ≤ 0.05) values of plasma albumin, total protein, and globulins. Plasma HDL-C highest concentrations (P ≤ 0.05) were reported in fish fed diet supplemented with 6 mg/kg−1 either Bulk or Nano Cu, whereas values of plasma TG and VLDL-C declined as Cu supplementation level increased either from Bulk or Nano source. Also, the best (P ≤ 0.05) values of CAT and GPX were seen in fish given diet supplemented with 6 Nano-Cu mg/kg−1. Fillets of fish-fed Nano-Cu-supplemented diets showed a marked decline (P ≤ 0.05) in moisture and fat contents, while crude protein, ash, and Cu contents considerably increased in the fillet by dietary supplementation of Nano-Cu at both levels 3 and 6 mg kg−1. In conclusion, the supplemental diets with 3 or 6 Nano-Cu mg/kg−1 enhanced growth, feed utilization, body indices, fillet nutrient composition, hematological assay, plasma metabolites, immune, antioxidant activities, and intestinal morphometry of Nile tilapia.

Effects of a commercial feed additive (Sanacore®GM) on water quality, productive performance and blood profile of gilthead seabream (Sparus aurata)

The present study evaluated the effects of the inclusion of commercial feed additive (Sanacore® GM; SAN) in diets on growth and productive performance, digestive enzymes, intestinal microbiota, intestinal histomorphometry and blood profile of gilthead seabream (Sparus aurata). For this purpose, four diets containing 0.0% (the control), 0.1%, 0.2% and 0.4% SAN were formulated and offered to triplicate groups of fish (20–23 g) reared in cages (30 × 10 × 3 m) for ten weeks. Water quality parameters were regularly monitored during the experimental period. No marked variations (p > 0.05) were observed in water temperature, dissolved oxygen and pH values; meanwhile, substantially decreases in unionized ammonia and nitrite levels were specifically detected at the treatment of 0.4% SAN. Feeding the fish on SAN-supplemented diets confirmed significant modulations in fish growth and production, haemato-biochemical profile, intestinal microbiota and intestinal histomorphometry. Fish growth, production and feed utilization indices extensively multiplied alongside with the increase in dietary SAN levels achieving their optimum values at the treatment of 0.4% SAN in contrast to the control group (0% SAN). Intestinal α-amylase, lipase and proteases activities were notably greater in fish fed with SAN-supplemented diets in particular at the 0.4% SAN diet. Feeding gilthead seabream on SAN-containing diets markedly increased red blood cell counts, haemoglobin level and haematocrit per cent mainly at the diet of 0.4% SAN. Compared with the control group, highest values of serum total protein, albumin and globulin accompanied with lowest values of alanine and aspartate aminotransferase were significantly recorded in fish fed on the 0.4% SAN diet. Intestinal microbiota were additionally modulated due to SAN administration to gilthead seabream. However, marked reductions in counts of Vibrio sp. and Escherchia coli alongside with high Bacillus sp. counts were obtained in fish mid-intestine mainly at the 0.4% diet. Feeding gilthead seabream on SAN-enriched diets confirmed higher villi length/width, absorption area and crypt depth than the control group with optimal values at the 0.4% SAN diet. According to the outcomes observed in this study, the SAN administration to gilthead seabream, especially at the 0.4% level led to considerable enhancements in overall growth and production performance via improving the secretion of digestive enzymes and prompting the intestinal morphometry and beneficial microbiota.

An online survey of dietary quality during complementary feeding; associations with maternal feeding self-efficacy and adherence to dietary recommendations

BackgroundParents are the gatekeepers of nutrition in early life and their feeding practices form children’s dietary behaviours. Although maternal characteristics have been associated with certain feeding practices, their relationship with overall quality of complementary feeding diets has not been explored. This study aimed to: assess dietary quality in complementary feeding age; explore its association with maternal and child characteristics; and evaluate the association between complementary feeding practices and child weight.MethodsAn online cross-sectional survey captured data from a self-selected sample of mothers living in the UK with a healthy full-term child in complementary feeding age. A total of 466 mothers completed a questionnaire on their complementary feeding practices, demographics, anthropometrics, rates of maternal food neophobia, feeding self-efficacy, social support, postnatal depression and infant temperament. Dietary quality was assessed using the Complementary Feeding Utility Index (CFUI). Children were classified into underweight, normal weight, overweight and obese.ResultsMajority of participants reported high levels of dietary quality as determined by a mean CFUI score of 80%. High dietary quality was associated with reliance on the NHS recommendation on timing of complementary feeding and maternal self-efficacy in promoting a healthy diet and limiting non-recommended foods. Responsive feeding, longer breastfeeding duration, frequent exposure to fruits and to a high variety of protein-rich animal foods were significantly associated with lighter child weight status. Consumption of sweetened drinks and delayed introduction of lumpy foods were associated with heavier child weight status.ConclusionsThis study provided an evaluation of dietary quality in complementary feeding in a UK sample of children and explored its relationship with maternal and child attributes. Increasing understanding of the current complementary feeding recommendations and strengthening maternal feeding self-efficacy may be key for healthcare professionals and researchers to improving complementary feeding practices.

Influence of Calcium and Nonphytate Phosphorus (NPP) on Meat-Type Quail’s Growth, Carcass Features, and Tibia Indices

This study aimed to evaluate the role of increasing dietary calcium (Ca) and non-phytate phosphorus (NPP) supplementation on the growth, carcass, edible portions, and tibia indicators of growing quail. The current study was conducted in a 3×3 factorial design, for this, 360 1-wk-old quails were haphazardly assigned to nine groups, each group is with three gradual levels of Ca (0.60, 0.90, and 1.20 %) and NPP (0.20, 0.40 and 0.60 %). Each group was divided into five replicates with eight-quail each. Results of the study suggested that except at 2 and 6 weeks of age, dietary Ca level did not exhibit any significant (P &gt; 0.05) impact on body weight. Similarly, in the case of NPP, apart from the live weight at 2 and 3 weeks of age, NPP did not have a significant impact on live body weight. Further, in comparison to the low Ca level, the moderate or high Ca levels have higher values of body weight gain. During all the experiments, dietary Ca, NPP, or their mixtures had no significant (P &gt; 0.05) impact on feed consumption. Similarly, feed conversion rate and carcass metrics were also not affected by the individual or combined application of Ca or NPP supplementation Similarly, dietary intakes of Ca or P did not have any significant effect on the various tibia indicators (P &gt; 0.05). Results of the study can be concluded that the effect of the Ca and NPP levels in Japanese quail diets is lowered and it does not much affect the growth rate, feed utilization, carcass yields, edible components, or tibia indices.

The green microalga Scenedesmus quadricauda modulates the performance, immune indices, and disease resistance of Nile tilapia fingerlings

Microalgae have been efficiently used as a feed supplement to enhance the fish performance and welfare because of their unique nutritional properties and functional bioactive ingredients. In this context, the current study assessed the effects of enriching fish diets with the green microalga Scenedesmus quadricauda (SQ) on the growth, digestive enzymes, antioxidant status, mucosal and innate immunity biomarkers, and serum bactericidal activities in Nile tilapia (Oreochromis niloticus) fingerlings. However, SQ was mixed with the ingredients of the basal diet in a dose of 0.0 (defined as control), 5.0, 10.0, 15.0, and 20.0 g/kg diet and then fed to fish daily for 60 days. Supplementing diets with SQ significantly prompted the growth and feed utilization indices of Nile tilapia with optimum results at 15 g/kg diet. Dietary SQ significantly (P < 0.05) improved activities of digestive enzymes (lipase, α-amylase, and protease), blood proteins (albumin, globulin, and total protein), antioxidant enzymes (glutathione peroxidase, superoxide dismutase, and catalase), and skin mucosal and serum innate immunity indices (lysozyme, total immunoglobulins, and complement C3). Conversely, serum malondialdehyde levels and activities of alanine and aspartate transaminase were significantly (P < 0.05) declined in fish fed with SQ-enriched diets. Serum bactericidal activities against Streptococcus agalactiae, Vibrio vulnificus, Pseudomonas fluorescens, and Aeromonas sobria were significantly higher at SQ-fed treatments, reaching their highest inhibition activities in the treatments of 15–20 g/kg diet. The present study evoked that enriching fish diets with 15 g SQ/kg diet provided marked enhancements in growth, antioxidant, and immune responses of Nile tilapia fingerlings.

Incorporating hydrolyzed soy protein or black soldier fly (Hermetia illucens) larvae meal into feeds for Totoaba macdonaldi

A 7-week study was conducted to evaluate the replacement of fishmeal (FM) by hydrolyzed soy protein (HSP) or black soldier fly larvae meal (BSFM) in diets for Totoaba macdonaldi juveniles (2.5 ± 0.1 g). A control diet containing FM as the main protein source was formulated with crude protein and crude fat contents of 52% and 14%, respectively. Then, in a series of isoproteic and isocaloric diets, HSP was incorporated at levels of 15 and 25%, or partially defatted BSFM at levels of 25 and 40%, in place of FM by weight. Fish fed the control diet and the diet containing HSP at 15% FM replacement had similar performance across all growth parameters, feed utilization, and body indices. In contrast, fish fed HSP at 25% FM replacement had significantly inferior final weight (46.59 g) and FCR (1.19). Fish fed BSFM at both levels of inclusion (25 and 40%) resulted in significantly reduced growth (final weight of 48.11 and 42.8 g, respectively) and also worse FCR (1.06 and 1.30, respectively), as compared to fish fed the control diet (final weight and FCR of 59.72 g and 0.94, respectively). Minimal changes in whole body proximate composition of fish and no changes in proximate and amino acid composition of muscle tissue were observed in response to dietary HSP or BSFM. Compared to fish fed the control diet, the fold change in trypsin gene expression increased significantly in fish fed 25% HSP, but not in fish fed 15% HSP. A similar numerical trend was observed for chymotrypsin gene expression, although differences were not statistically significant (P = 0.0768). No significant differences were observed for the gene expression of both enzymes in response to dietary BSFM; regulation of both proteases appears to take place at a transcriptional level. In summary, at least 15% of dietary fishmeal can be replaced by HSP without altering growth, survival, or any feed utilization and body indices of T. macdonaldi juveniles. Conversely, fish fed diets replacing 25% FM by HSP or by 20 and 40% BSFM displayed significantly inferior growth.

Effects of marine hydrolysates in wheat gluten meal‐based diet on the growth, haemato‐biochemical, immunological and antioxidant status of GIFT tilapia reared in floating cages

This study was conducted to evaluate the effects of supplementation of tuna hydrolysate (TH), squid hydrolysate (SH) and mixture of both hydrolysates in wheat gluten meal (WGM)-based diets on the growth, haemato-biochemical, immunological parameters and antioxidant indicators of GIFT tilapia. Experimental fish were fed different diets, namely a control diet containing fishmeal (FM) without WGM and hydrolysate; a WGM diet without FM and hydrolysate (WGM); a WGM diet without FM and 5 g/kg TH (WGM-TH); a WGM diet without FM and 5 g/kg SH (WGM-SH); and a WGM diet without FM and mixture of 5 g/kg of TH and SH (WGM-Mix). A total of 450 fish (9.83 ± 0.01 g) were fed on the five experimental diets in triplicate groups for 8 weeks. The growth performance and feed utilization indices of the fish were found to be significantly higher in WGM supplemented with TH diet followed by WGM-SH, WGM-Mix and WGM diets. There was no significant impact in blood and serum biochemical parameters among the treatments. The immunological and antioxidant indicators were not significantly different between hydrolysate-supplemented diets; however, they were significantly greater than hydrolysate-unsupplemented diets (control and WGM diets). Based on the results, it is suggested that FM can be replaced by WGM for better growth performance even without the supplementation of hydrolysates, whereas hydrolysates are considered important for better immunological responses and antioxidant status of GIFT tilapia.

Valorization Use of Amphipod Meal, Gammarus pulex, as a Fishmeal Substitute on Growth Performance, Feed Utilization, Histological and Histometric Indices of the Gut, and Economic Revenue of Grey Mullet

The future of aquaculture development is directed toward high intensification to overcome the decline in natural fishing and to provide enough protein for the increasing world population. The spread of aquaculture production and intensification requires the search for high-quality, new efficient feed ingredients with low cost and sustainable importance. Therefore, the current study aimed to detect the effects of partial or total replacement of fishmeal with amphipod meal, Gammarus pulex, on growth performance, survival percent, feed utilization, histological alteration of intestine and liver, and economic yield of grey mullet, Mugil cephalus, fry. Five diets were formulated to contain 100% fishmeal (FM), or FM replaced with 25%, 50%, 75%, or 100% amphipod meal (APM) (D0, D25, D50, D75, and D100, respectively). A total of 300 grey mullet fry (0.097 ± 0.001 g), were divided into five groups (three replicates each) at an initial stocking density of 20 fry per aquaria (100 L). The aquarium’s water is renewed at a rate of 30% daily. During a 60-day experimental period, the feeding rate was 20% of body weight, which was introduced as five meals per day. Fish fed D50 achieved the highest significant values of final weight (1.80 g), weight gain (1.70 g), survival (86.67%), final length (4.47 cm), and length gain (2.06 cm). In addition, the feed utilization of diets containing increasing substitution levels of FM showed that the highest protein intake (0.82 g ish−1), protein efficiency ratio (0.83), protein productive value (30.65%), and the lowest significant feed conversion ratio (1.21) were recorded with D50. The dose-response study revealed that the best substitution levels could range between 50% and 75%. Histological observations confirmed that the highest number of goblet cells and intestinal villi were recorded in the group fed D50. No pathological effect was observed in the liver at all substitution levels. In terms of economic efficiency, the best economic conversion ratio was recorded in the group fed D50. This study confirmed that 50% partial substitution of FM with APM is the ideal replacement level for grey mullet fry. In addition, the use of a new renewable alternative, such as APM to substitute FM, could relieve the pressure on the capture of wild fish and reduce the environmental impact of inland aquaculture.

Implications of dietary Delonix regia seed meal on growth, feed utilization, haematology and fillet yield of red Nile tilapia Oreochromis niloticus

Delonix regia is commonly called Flamboyant or flame of the forest. The seeds were fermented, boiled, sundried and then ground into powdered meal. 40% crude protein based test diets containing Delonix regia seed meal D0 = 0%; D15 = 15%; D20 = 20% and D25 = 25% inclusion levels respectively were prepared. Red tilapia (Oreochromis niloticus) fingerlings of 6 weeks old were acclimatized for two weeks and then stocked in 12 hapas at 15 fish per hapa measuring 0.6 m × 1.2 m × 0.7 m placed in a concrete tank. Each diet was assigned to fish in a separate hapa in triplicate and administered at 3% fish body weight per day for 16 weeks. Fish weight and length were taken initially, bi-weekly and terminally. Water quality was monitored weekly. Number of fish at the end was recorded and survival rate, growth, feed utilization, fillet yield and blood parameters were determined. The data were subjected to the analysis of variance and mean separation (P= 0.05). Survival rate was highest in fish raised on D20 and least in D25 without any significant difference across the range. Mean growth performances, feed utilization indices and fillet yield were generally congruent between D20 and D25 with varying degrees of significant difference to other feeds. Results of blood assay did not depict harmful effects of the test diets indicating that the fish enjoyed some good measures of health. The gross performance of fish on D20 was optimal. It was therefore concluded that 20% dietary inclusion level of fermented, cooked and dried flamboyant seed was the best for the red tilapia (Oreochromis niloticus) post fingerlings.

Production and economics of probiotics treated Macrobrachium rosenbergii at different stocking densities

The effect of stocking density on growth, production, feed utilization and condition factor of probiotic treated Macrobrachium rosenbergii were analyzed in the present study. Juvenile prawn of weight 3.48 ± 1.4 g was stocked at the densities of 2, 3, 4 and 5 individuals/m2 respectively in T1, T2, T3 and T4. A supplementary diet containing 32% protein was used with the commercial feed probiotics Zymetin daily and soil probiotics Super PS weekly. After 180-days culture-period, significant differences in growth parameters were observed between different treatments (F3,645 = 228.81, P < 0.01). The highest and lowest final mean body weight (56.95 ± 6.7 g and 30.85 ± 11.43 g), weight gain (47.47 ± 6.74 g and 27.37 ± 11.43 g), specific growth rate (1.49 ± 0.07% BW/day and 1.18 ± 0.19% BW/day), and survival rate (88.43 ± 0.46% and 69.23 ± 0.32%) were found in T1 and T4, respectively. The treatments containing lower stocking densities showed better feed utilization indices; and except T4, higher stocking densities showed better gross production. The length-weight analysis showed positive allometry in T1, T2 and T3; whereas, it was isometric in T4. The condition factors varied between 0.80 and 1.16 indicating the healthy condition of the prawns in all groups. Water quality parameters were found within the acceptable limits in all treatments. Probiotic treated prawn cultured with the density of 3/m2 obtained highest gross return, and net returns to land, family labor and management, would be considered for the best practice of commercial prawn production.

Probiotic yeast enhances growth performance of Nile tilapia (Oreochromis niloticus) through morphological modifications of intestine

Probiotics, an eco-friendly alternative to antibiotics application appears to have strong potential for improving the sustainability of aquaculture. The aim of the study was to evaluate the effect of probiotic brewer’s yeast, Saccharomyces cerevisiae supplementation on growth performance, feed utilization and intestinal morphometry of Nile tilapia, Oreochromis niloticus. A feeding trial of 60 days was conducted in which tilapia fingerlings (7.55 ± 1.25 g) were randomly distributed into three replicate aquaria under four different treatment groups, receiving S. cerevisiae at 0, 1, 2 and 4 g kg−1 diet, respectively. At the end of the feeding trial, growth performance parameters (weight gain, WG; % WG; specific growth rate, SGR), feed utilization indices (protein efficiency ratio, PER; feed conversion ratio, FCR) and intestinal morphology were assessed. The results obtained from this study revealed that growth performance and feed utilization indices were increased significantly in the fish fed with 4 g kg−1S. cerevisiae supplemented diet compared to controls. The length, width and area of villus were significantly enlarged in fish fed 4 g kg−1S. cerevisiae supplemented diet. Likewise, intestinal mucosal fold, width of lamina propria, width of enterocytes and number of goblet cells increased in the fish fed with 4 g kg−1S. cerevisiae supplemented diet. These results demonstrated that S. cerevisiae can be effectively recommended as an important growth promoter for tilapia culture.

Probiotic yeast enhances growth performance of rohu (Labeo rohita) through upgrading hematology, and intestinal microbiota and morphology

Probiotics play an important role as bio-friendly substances in ensuring the sustainability and profitability of aquaculture. In the present study, we examined the effects of probiotic brewer's yeast, Saccharomyces cerevisiae on growth, feed utilization, hemato-biochemical indices, intestinal microbiota and intestinal morphometry of rohu, Labeo rohita. A trial of 90 days was conducted in which rohu fingerlings were fed under four different treatment groups in aquaria, receiving S. cerevisiae at 0, 1, 2 and 4 g/kg diet, respectively. Growth parameters (weight gain and specific growth rate), feed utilization (feed conversion ratio and protein efficiency ratio), hematobiochemical indices (hemoglobin, red blood cell, white blood cell and glucose), intestinal microbiota (total viable, lactic acid bacteria and yeast count) and intestinal morphology (villi length, villi width, crypt depth, thickness of villi wall etc.) were analyzed at the end of feeding trial. The results demonstrated substantial development in the growth performance, feed utilization and hematobiochemical indices in rohu fed probiotic incorporated diet compared to control diet. There were noticeable variations in intestinal microbiota and intestinal morphology between the treated and control diet fed groups. These results revealed that S. cerevisiae has a potential influence as an essential probiotic to improve the digestion, absorption, assimilation of nutrients through the improvement of gut microbiota and morphometry of L. rohita. Thus, S. cerevisiae can be effectively recommended as an important growth promoter for rohu.

Ginkgo biloba leaf extract improves growth, intestinal histomorphometry, immunity, antioxidant status and modulates transcription of cytokine genes in hapa-reared Oreochromis niloticus

This study was designed to evaluate the impacts of dietary supplementation with Ginkgo biloba leaf extract (GBL) on the growth, intestinal histomorphometry, immunity, antioxidant status, and expression of cytokine genes in Nile tilapia reared in the hapas. A control diet was enriched with different GBL levels (0.0, 5.0, 7.0, and 9.0 g/kg) to form 4 experimental diets and were fed to Nile tilapia for 8 weeks. The findings illustrated that dietary GBL significantly enhanced the growth and feed utilization indices compared to those reared in the control group. A dose-dependent increase of hepatic catalase, superoxide dismutase, and glutathione peroxidase activities alongside a decline of hepatic malondialdehyde levels were recorded in GBL groups compared with the control. Serum lysozyme activity, complement C3, and immunoglobulin M levels were significantly increased in GBL groups compared with the control group. Moreover, dietary GBL maintained the normal intestinal and hepatopancreatic histological structures with a significant increase of some histomorphometric measurements of proximal, middle, and distal intestinal parts of the treated fish. Interestingly, dietary GBL supplementation significantly increased the mRNA expression of interleukin-1 beta (IL-1β), IL-6, IL-10, tumor necrosis factor alpha (TNF-α) and interferon gamma (INF-γ) genes in the splenic tissues of treated fish over the control group. To conclude, it could be recommended to use GBL as a functional phytogenic feed additive to improve the growth, hepatic and intestinal health status, hepatic antioxidant status, and immunity of treated Nile tilapia. Besides, the second order polynomial regression revealed that 7.50 g GBL/kg diet is the optimal inclusion level to improve growth with no negative impacts on the overall health condition of treated Nile tilapia.

Black Soldier Fly, Hermetia illucens as an Alternative to Fishmeal Protein and Fish Oil: Impact on Growth, Immune Response, Mucosal Barrier Status, and Flesh Quality of Juvenile Barramundi, Lates calcarifer (Bloch, 1790)

Simple SummaryFishmeal and fish oil being recognized as nutritionally balanced and preferred protein and lipid sources in aquafeeds for finfish farming. However, the limited supply, soaring prices, and depletion of wild capture fisheries have prompted the aquaculture industry to look for widely available and less expensive alternatives for fishmeal and fish oil to ensure the sustainability of aquaculture production. As an alternative to fishmeal protein and oil, black soldier fly (BSF) larvae is considered a promising candidate for its high protein, lipid and minerals content, as well as for its bioactive potential with anti-microbial, anti-fungal, and anti-viral functions. This study investigated the effects of partial substitution of fishmeal protein and fish oil with partially defatted BSF larvae protein and oil on growth performance, non-specific immunity, mucosal barrier status and muscle fatty acids composition in barramundi. The findings of the study confirmed that BSF could substitute 30% fishmeal and fish oil successfully without compromising the growth of barramundi. Further, partial replacement of fishmeal and fish oil with BSF diets improved bactericidal activity, immune-related cytokine expression, and mucin cells in both gut and skin which are an indication of improved immunity of barramundi.A feeding trial was conducted to test the effects of partial replacement of fishmeal (FM) protein and fish oil (FO) with partially defatted black soldier fly, Hermetia illucens insect protein, and oil, respectively, on growth performance, immune response, gut and skin barrier status, and flesh quality in juvenile barramundi. Four isonitrogenous and isocaloric diets used in the study were a control diet based on FM, 30% FM replaced with H. illucens protein (HiP), 30% FO replaced with H. illucens oil (HiO), and both 30% FM and 30% FO replaced with H. illucens protein and oil (HiPO). Diets were fed twice a day to satiety in triplicated groups of barramundi with an initial body weight of 1.74 ± 0.15 g per fish. At the end of the trial, growth and feed utilization indices were found insignificant (p > 0.05) between the test diets and control. A significant increase in bactericidal activity was observed in fish fed the HiP diet while serum lysozyme activity was unchanged. Stress-related heat shock proteins (HSP70 and HSP90) did not differ significantly among the test diets while immune-relevant genes (IL-1β and IL-10) were significantly upregulated in HiP and HiOP groups. The number of mucin cells were increased in the gut and skin of HiP and HiOP fed fish when compared to the control diet. The total fatty acid compositions (∑SFA, ∑MUFA, ∑PUFA, ∑n-3, and ∑n-6) in the muscles of barramundi were not significantly influenced with H. illucens protein and oil diets when compared to the control.