Search

Carbohydrates serve as essential macronutrients in aquaculture feeds, providing cost‐efficiency and numerous advantages, including energy supply, pellet stability, reduced ammonia excretion, and support for exoskeleton synthesis in crustaceans. Despite their significance, research on carbohydrate nutrition in crustaceans has been relatively limited compared to finfish. This comprehensive review addresses this knowledge gap by presenting contemporary insights into carbohydrate utilization in commercially important crustacean species, encompassing shrimps, prawns, crabs, lobsters, and crayfishes. The review underscores the pivotal role of carbohydrates, identifies limiting factors, and outlines strategies for enhancing efficiency. Wheat and sorghum/milo emerge as particularly promising carbohydrate sources. Nevertheless, determining species‐specific carbohydrate inclusion levels remains essential for further investigation. This review also emphasizes species‐specific distinctions in carbohydrate utilization during starvation, influenced by factors such as age, moulting stage, and digestive capacity. Challenging the misconception that carbohydrates are superfluous for crustaceans is imperative. Additional research to advance comprehension of their utilization mechanisms is vital. Enhanced knowledge of carbohydrate utilization can pave the way for economically sustainable and environmentally friendly feeds in crustacean aquaculture. Furthermore, exploring exogenous enzyme potential, optimizing pre‐treatment methodologies, and harnessing probiotics can further augment carbohydrate utilization. These advancements hold promise for bolstering the growth and sustainability of the crustacean industry, meeting the surging demand for seafood production while minimizing environmental impact. [ABSTRACT FROM AUTHOR]

A feeding trial was conducted to explore the effect of dietary Houttuynia cordata leaf extract (HCLE) and leaf meal (HCLM) on immunological responses and expression of interferon‐gamma (IFN‐γ) and tumour necrosis factor‐alpha (TNF‐α) gene in Labeo rohita fingerlings. Six isonitrogenous (350 g/kg CP) and isocaloric (17 MJ/kg DE) purified experimental diets were formulated with Houttuynia cordata leaf extract and leaf meal comprising control, C (0 g/kg HCLE and HCLM), E2.5 (2.5 g/kg HCLE), E5 (5 g/kg HCLE), E10 (10 g/kg HCLE), M10 (10 g/kg HCLM) and M20 (20 g/kg HCLM). Labeo rohita fingerlings (3.37 ± 0.23 g) were distributed in six experimental groups in triplicates following the complete random distribution. Fish were fed twice daily with respective experimental diets for a period of 60 days. A significantly (p <.05) lower lactate dehydrogenase, malate dehydrogenase, superoxide dismutase and catalase activities were registered in supplemented groups compared with control group, while respiratory burst and lysozyme activities were significantly (p <.05) higher in E10 group compared with other experimental groups. Haemoglobin, total leucocyte count, total erythrocyte count and haematocrit values were significantly (p <.05) higher in E10 group. The expression of IFN‐γ and TNF‐α in both the kidney and liver was significantly up‐regulated in leaf extract and meal supplemented groups with the highest expression in the fish of E10 group. Overall, these results suggest that the dietary supplementation of ethanolic extract of the Houttuynia cordata leaf at 10 g/kg level can enhance the immune response of L. rohita fingerlings. [ABSTRACT FROM AUTHOR]

A protein isolate was prepared from karanj seed (KPI) with 921.2 g protein/kg seed, which contained a negligible amount of anti‐nutritional factors and a balanced amino acid composition, especially rich in methionine. For 60‐day feeding trial, five isonitrogenous (300 g/kg CP) and isocaloric (15 MJ DE/kg) diets were formulated by replacing soybean protein isolate (SPI) on protein equivalent basis, KPI‐0 (control, 0 g/kg KPI); KPI‐25 (replacing 250 g/kg SPI protein with KPI); KPI‐50 (replacing 500 g/kg SPI protein with KPI); KPI‐75 (replacing 750 g/kg SPI protein with KPI) and KPI‐100 (replacing 1,000 g/kg SPI protein with KPI) for the feeding of L. rohita. The weight gain percentage, specific growth rate, feed conversion ratio and protein efficiency ratio were not significantly (p >.05) varied among the KPI fed and control groups. A significantly higher hepatosomatic index was recorded in the control and KPI‐25 groups compared with other groups. The whole‐body compositions, except ether extract, did not differ significantly (p >.05) among the groups. Digestive (amylase, protease, lipase and alkaline phosphatase) and metabolic enzyme activities (hexokinase, transaminases and lactate dehydrogenase) and glycogen stores were not significantly affected, whereas intestinal alkaline phosphatase differed significantly (p <.05). The RNA–DNA ratio was significantly (p <.05) higher in the KPI‐75 group. Thus, the study revealed that KPI can completely replace SPI protein at 191 g/kg inclusion level in the diets of L. rohita fingerlings. [ABSTRACT FROM AUTHOR]

This study was conducted to illustrate the effect of dietary gelatinized starch (GS) on the growth performance, enzyme activities and expression of MyoD and Myf5 in magur, Clarias batrachus fingerlings. Four iso‐nitrogenous (37%) and iso‐lipidic (6%) diets containing 15% (D‐1), 25% (D‐2), 35% (D‐3) or 45% (D‐4) GS were fed to 240 fingerlings (2.5 ± 0.5 g) in triplicates groups for 8 weeks. The maximum weight gain %, specific growth rate, protein efficiency ratio, lower FCR and higher mRNA expression of MyoD or Myf5 were found in the D‐3 group fed with 35% GS. Higher hepatosomatic index, viscerosomatic index, body lipid and lower moisture content were found in the D‐4 group. Aspartate transaminase and alanine transaminase activities were found to be higher in the D‐1 group. Amylase, glucose‐6‐phosphate dehydrogenase and blood glucose were higher in the D‐4 group. Superoxide dismutase, catalase and hexokinase activities remain unaffected by the dietary GS levels. Hence, the overall results indicate that 35% GS can improve growth performance and upregulate myogenic regulatory factors, but 45% GS level will favor lipogenesis and compromise growth. Furthermore, Myf5 gene showed more immediate response than the MyoD to the dietary carbohydrate in magur. [ABSTRACT FROM AUTHOR]

Abstract: A 60‐day feeding trial was conducted to determine the growth performance and expression of insulin‐like growth factor 1 gene (IGF‐I gene) in Labeo rohita fingerlings fed with either raw, soaked or fermented sweet potato leaf meal (SPLM) by completely replacing de‐oiled rice bran (DORB), following a completely randomized design. Seven isonitrogenous (30%) and isocaloric (1.8 MJ/100 g) diets were prepared by replacing DORB with 50% and 100% raw, soaked and fermented sweet potato leaf meal, maintaining DORB‐containing diets as a control. Weight gain %, SGR (specific growth rate) and PER (protein efficiency ratio) were significantly (p < 0.05) higher when 100% DORB was replaced by fermented SPLM in comparison to other treatment groups. The fermented and soaked SPLM‐fed groups had registered with lower FCR value. The expression of growth regulating gene IGF‐I mRNA and RNA/DNA ratio was found to be significantly higher (p < 0.05) in soaked and fermented SPLM‐fed groups. In this study, the body protein and lipid composition did not vary significantly (p > 0.05). Hence, the study concludes that the fermented sweet potato leaf meal using Chaetomium globosum can replace 100% DORB in the diet of Labeo rohita without any detrimental effect on growth performance. [ABSTRACT FROM AUTHOR]

A feeding trial was conducted for 90 days to assess the metabolic and digestive enzyme activity in response to alternate or mixed feeding of different protein levels in the diet of Pangasianodon hypophthalmus fingerlings. One hundred and forty four fingerlings with an average weight of 5.0-5.5 g were distributed into four experimental groups each with triplicate. Four iso-caloric diets with varying level of crude protein viz., 35%, 30%, 25% and 20% were made and designated as diet 35P, 30P, 25P and 20P respectively. Four treatments were maintained based on four different feeding schedules such as continuous feeding of diet 35P (35P/35P), alternate feeding of 1 day diet 35P next day diet 30P (35P/30P), alternate feeding of 1 day diet 35P next day diet 25P (35P/25P) and alternate feeding of 1 day diet 35P next day diet 20P (35P/20P). As a result, specific growth rate ( SGR) and weight gain percentage were relatively higher in treatment (35P/25P) followed by (35P/35P) and (35P/30P). The metabolic enzymes such as lactate dehydrogenase ( LDH), malate dehydrogenase ( MDH), glucose-6-phosphate dehydrogenase (G6 PDH), Glucose-6-phosphatase (G6Pase), alkaline phosphatase ( ALP), acid phosphatase ( ACP), alanine aminotransferase ( ALT), aspartate aminotransferase ( AST) were expressed better in (35P/35P) group followed by (35P/25P) and (35P/30P) groups. The digestive enzymes, protease and lipase activities were higher in (35P/35P) and (35P/25P) groups. The present study revealed that the better nutrient utilization and growth of 35P/25P group is because of their balanced digestive and metabolic enzyme activities through alternate level of higher and lower protein diet. [ABSTRACT FROM AUTHOR]