Effect of feeding frequency on performance, nutrient digestibility, energy and nitrogen balances in juvenile African catfish (Clarias gariepinus) fed diets with two levels of crystalline methionine

Folasade E Elesho,Saskia Kröckel,Elisa Ciavoni,David A.H Sutter,Johan A.J Verreth,Johan W Schrama

doi:10.1016/j.anifeedsci.2021.115098

Abstract

In this study, the effect of feeding frequency and its interaction with crystalline methionine supplementation level on performance, digestion, energy and nitrogen balances was assessed. The experiment had a 2 × 4 factorial design, testing two levels of crystalline methionine (Met) and four feeding frequencies. The two diets contained Met either just fulfilling or exceeding the Met requirement of African catfish (Clarias gariepinus). African catfish with initial mean weight of 44 g were allocated to one of four feeding frequencies (six, two, one time (s) per day and two times out of three days) in a recirculation aquaculture system. Fish were fed an equal daily ration for 32 days. Performance parameters, nutrient digestibility, body composition, and nutrient balances were evaluated. Except for digestible nitrogen intake and dry matter body content, none of tested parameters was affected by the interaction between dietary Met levels and feeding frequencies. Growth, energy and nitrogen gain were unaffected by feeding frequency as well as dietary Met level. FCR was low, being 0.84 averaged over all treatments. However, feeding frequency affected feed intake and the apparent digestibility coefficient (ADC) of nutrients. Feeding at lowest frequency was accompanied by a lower feed consumption compared to other frequencies (P < 0.001). At higher frequency, ADC was higher for macronutrients but lower for phosphorus and magnesium. It was concluded that the asynchronous availability of AA for protein synthesis, which is often suggested to cause a sub-optimal utilization of crystalline AA, was not influenced by feeding frequency. However, feeding at a low frequency hampered daily feed intake of African catfish. Whereas, higher frequency improved nutrient digestibility, though it did not result in improved growth probably due to the higher energy required for maintenance related to physical activities at higher frequency.

Highlights

Plant protein sources are increasingly used as alternative to marine protein sources in fish diets
This study was conducted to assess the interaction effect of feeding frequency and dietary crystalline methionine level on nutrient digestibility, nitrogen and energy balances in African catfish. Thereby, it investigated the underlying factors causing sub-optimal amino acid (AA) utilization in fish, especially when plant ingredients are used as protein source
Some authors have reported that this problem is often caused by the asynchronous availability of dietary protein-bound AA and crystalline amino acid (CAA) supplemented to an AA-deficient diet (Ambardekar and Reigh, 2007; Zarate et al, 1999)

Summary

Introduction

Plant protein sources are increasingly used as alternative to marine protein sources in fish diets. Dietary addition of crystalline methionine improved the growth of African catfish when fed diets based on plant-protein (Elesho et al, 2021) Species such as channel catfish (Ictalurus punctatus), carp (Cyprinus carpio), hybrid striped bass (Morone saxatalis F X Morone chrysops M) and tilapia (Oreochromis niloticus) have been reported to utilize CAA less efficiently compared to protein-bound AA in the diet (Lumbard, 1997; Nose and Lee, 1974; Teshima, 1990; Yamada et al, 1981; Zarate et al, 1999). It is suggested that this difference in moment of absorption may result in quick catabolization of the absorbed CAA and lost rather than used for protein synthesis (Ambardekar and Reigh, 2007; Nwanna et al, 2012)

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