Differences in energy utilization efficiency of digested protein, fat and carbohydrates in snakehead (Channa striata)

L.T.T Phan,K Masagounder,J Mas-Muñoz,J.W Schrama

doi:10.1016/j.aquaculture.2020.736066

L.T.T Phan, K Masagounder + Show 2 more

Open Access

https://doi.org/10.1016/j.aquaculture.2020.736066

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Journal: Aquaculture	Publication Date: Oct 17, 2020
Citations: 10	License type: cc-by

Affiliation: Wageningen University & Research, Evonik (Germany)

Abstract

This study aimed to assess if the relationship between digestible energy (DE) intake and energy retention (RE) is dependent on dietary macronutrient composition; and to quantify the energy utilization efficiency of digested protein (dCP), fat (dFat) and carbohydrates (dCarb) for growth in snakehead (Channa striata). This was achieved by conducting a 42-day feeding trial on snakehead (29.1 g) with a 4 × 2 factorial design. Nutrient digestibility, nitrogen and energy balances were measured. Four diets were formulated, which had contrasting levels of protein, fat and carbohydrates. Each diet was tested at 2 feeding levels, in order to estimate within each feeding level the relationship between DE and RE. Snakehead (a carnivore) is well able to digest starch. Starch digestibility ranged from 93% to 99.5%. The linear relationship between RE and DE intake was affected by diet. Diets with a high Carb content had a lower slope (0.45 versus 0.53 to 0.56), which indicates that DE is less efficiently used for RE. Multiple regression of RE as a function of dCP, dFat and dCarb (in g.kg-0.8.d−1) intake was also applied to estimate the energy utilization efficiency of each digestible macronutrient. A linear relationship was found between RE and dCP, dFat and dCarb. Snakehead are a lean fish, which we observed prioritise digestible protein intake for protein gain. The estimated energy efficiencies of dCP, dFat and dCarb (respectively, kNE;dCP, kNE;dFat, and kNE;dCarb) for energy retention were 53, 79 and 5%, respectively. Snakehead can digest starch at the high level but cannot metabolise digested starch for growth efficiently.

Highlights

Snakehead (Channa striata), called murrel or haruan, recently became a widely farmed freshwater fish in South East Asia due to its rapid growth
The order of the response to the different diets were compar able at both feeding levels, but the absolute differences between the effect of diets were larger at the high feeding level compared to the low feed feeding levels
Digestible nutrient intakes, final body weight and growth were all affected by both feeding level, diet and their interaction (P < 0.001; Table 2 & supplementary Table S3)

Summary

Introduction

Snakehead (Channa striata), called murrel or haruan, recently became a widely farmed freshwater fish in South East Asia due to its rapid growth. This carnivorous species is an aggressive predator, which, as an obligate air-breather, can survive in shallow and slow moving waters (Shafri and Abdul Manan, 2012). The ingredients used for snakehead feed appear to be increasingly diversified (Zehra and Khan, 2012, Hien et al, 2017, Aliyu-Paiko and Hashim, 2012) This leads to an increased variation in the composition of digested macronutrients. Effects of this diversification on the energy metabolism has not been assessed for snakehead

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