Growth Performance, Growth-Related Genes, Digestibility, Digestive Enzyme Activity, Immune and Stress Responses of de novo Camelina Meal in Diets of Red Seabream (Pagrus major).

Kumbukani Mzengereza,Tomonari Kotani,Ronick S Shadrack,Saichiro Yokoyama,Seok Seo,Mohammed F El Basuini,Serge Dossou,Mahmoud A O Dawood,Shunsuke Koshio,Zhang Yukun,Manabu Ishikawa

doi:10.3390/ani11113118

Abstract

Simple SummaryFish meal (FM) is the major protein source in aquafeed to achieve sustainable aquaculture production. However, the supply of FM is low due to high cost and low availability. There is ongoing conceited research to identify alternative viable protein sources to replace the finite FM. Novel camelina meal (CM) is a plant protein with high amino acids levels and has been tested as an alternative protein source in livestock feeding. However, there is limited information on supplementation of the CM in aquaculture diets. In this study, four diets were formulated to contain 0% plant protein, 205 g/kg soybean meal, and two levels of CM (205 g/kg and 330 g/kg) in diets fed to red seabream. Results indicated that adding CM 205 g/kg in diets-maintained growth performance, digestive enzyme activities, and nutrient digestibility regulated the immunity and stress resistance and modulated the growth-related genes in red seabream. These findings provide the first step in using novel CM and are essential for future practical formulations of feed for red seabream and other marine fish species.A 60-day experiment was designed to assess the effect of different ratios of fish meal (FM): camelina meal plant protein (CM) on growth response and relative gene expression of growth-promoting factors, feed utilization potency, digestive enzymes activities, apparent digestibility (ADC), stress response, non-specific immunity of Pagrus major. Four isonitrogenous (490.7 g/kg of crude protein) and isolipidic (91.5 g/kg total lipid) experimental diets were formulated and designated as camelina meal (CM0), soyabean meal (SBM20.5), CM20.5, and CM33 based on protein contents. At the end of the feed trial, significantly higher (p < 0.05) weight gain, specific growth rate, and feed intake but lower feed conversion ratio were recorded in fish fed CM0, SBM20.5, and CM20.5 than fish fed CM33. The lowest growth, feed utilization, enzyme activity, and digestibility were recorded in fish fed CM33. Significantly higher pepsin, amylase, and protease activities were observed in fish fed CM0, SBM20.5, and CM20.5 diets than fish fed CM33. The highest ADC of protein was recorded in fish fed CM0, SBM20.5, and CM20.5 diets. Hematocrit levels were depressed CM33 while total serum protein, total cholesterol, triglyceride, blood urea nitrogen, total bilirubin, aspartate aminotransferase, and alanine aminotransferase were not significantly changed by the inclusion of CM. Non-specific immune variables (lysozyme activity, peroxidase activity in serum and nitro blue tetrazolium) in fish fed CM0, SBM20.5, and CM20.5 were significantly higher than in fish fed CM33 diet. The superoxide dismutase of fish fed CM20.5 was not significantly different from CM0 and SBM20.5 (p > 0.05). Catalase and low salinity stress test show that CM0, SBM20.5, and CM20.5 were not significantly (p > 0.05) different, while CM33 was significantly lower than the rest of the diets. TBARs show that CM20.5 and CM33 diets were significantly different (p < 0.05), but CM20.5 was not significantly different from SBM20.5. Significantly higher hepatic IGF-1 and IGF-2 mRNA expression was found in fish-fed diet groups CM0, SBM20.5, and CM20.5 than fish fed CM33. The present study indicated that the addition of CM up 205 kg/kg to diet maintains growth, digestive enzymes, nutrient digestibility, immunity, stress resistance, and feed utilization efficiency of red sea bream.

Highlights

Fish meal (FM) is a primary protein ingredient in aquaculture enterprises
60 days feeding period in red seabream fed diets formulated by replacing fish meal with camelina meal at 0% for reference diet (CM0), 20.5 g/kg with soybean mean (SBM20.5), 20.5 g/kg with camelina meal (CM20.5) and 33 g/kg camelina meal (CM33)
Table biochemistry parameters obtained after 60 days feeding period in red seabream fed diets formulated by replacing fish meal with camelina meal at 0% for reference diet (CM0), 20.5 g/kg with soybean mean (SBM20.5), 20.5 g/kg with camelina meal (CM20.5) and 33 g/kg camelina meal (CM33)

Summary

Introduction

Fish meal (FM) is a primary protein ingredient in aquaculture enterprises. It is imperative to explore alternative protein sources in the aquafeed sector. Numerous proteins have been examined and recommended for use in aquafeed to lessen the inclusion of FM while maintaining the growth performance and health of cultured animals [4]. Scientific evidence shows that considerable quantities of FM in diets of Atlantic salmon can be substituted with plant protein without showing deleterious growth response and nutrient use [10]. Plant proteins have high proportions of anti-nutritional factors (ANFs) and fiber that diminish palatability, feed intake, and nutrient digestibility [12]. Plant protein meals have a positive influence if incorporated in adequate quantities in animal diets. Plant-based camelina meal (CM) is pegged at $260/metric ton compared to FM, which fetches $1385/metric ton [14]

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Conclusion