Effect of dietary protein to energy ratio on performance of nile tilapia and food web enhancement in semi-intensive pond aquaculture

Kabir Kazi, Schrama Johan W., Verreth Johan A.J., Phillips Michael J., Verdegem Marc C.J.. 2019. Effect of dietary protein to energy ratio on performance of nile tilapia and food web enhancement in semi-intensive pond aquaculture. Aquaculture, 499 : 235-242.

Quartile : Q1, Sujet : FISHERIES / Quartile : Q1, Sujet : MARINE & FRESHWATER BIOLOGY

Résumé : When fish have only access to formulated feed, the optimal dietary protein to energy ratio (P:E) for tilapia ranges between 18 and 23 g.MJ−1. In pond culture, where natural foods complement administrated feed, increasing the carbon:nitrogen (C:N) ratio stimulates the natural food productivity. This study assessed if lowering the dietary P:E ratio (and thus increasing the C:N ratio of the feed input in the pond) below the optimal P:E ratio affects fish productivity, food web dynamics and nitrogen balances in semi-intensively managed tilapia ponds. Twelve ponds, each divided into three equally-sized compartments, were assigned to test the effect of two diets, which differed in P:E ratio (19 vs. 14 g.MJ−1). Three feeding levels (no, “low” and “high”) were nested in each pond in a split plot design. Initial fish biomass was 1166 (±16) g.compartment−1 and the experiment lasted 60 days. Decreasing P:E ratio enhanced tilapia production and specific growth rate (P < .05; 1195 vs. 985 g.compartment−1 and 1.76 vs 1.55%.d−1). Body composition of tilapia was unaffected by diet and feeding level. Despite the difference in performance, final fat content was 5% of body weight and unaffected by treatments. Averaged over both diets, survival and feed conversion ratio increased with increasing feeding level (P < .001). Diet composition did not alter measured water quality, and abundance and diversity of the related parameters of the food web. The total amount of N accumulated in the pond− was lower with the low P:E ratio diet (i.e., low protein diet). The data on N gain and N balance at the pond level suggest that the food web productivity was stimulated by reducing the dietary P:E ratio below the reported optimal levels in the literature. It is hypothesized that the optimal dietary P:E ratio is dependent on the culture intensity (extensive, semi-extensive or intensive pond culture).

Mots-clés Agrovoc : Oreochromis niloticus, Tilapia, alimentation des poissons, régime alimentaire, élevage en étang, aquaculture, étang de pisciculture, composition des aliments, chaîne alimentaire, aliment pour animaux

Mots-clés libres : Pond, P:E ratio, Food web, N utilization

Auteurs et affiliations

• Kabir Kazi, Wageningen Institute of Animal Sciences (NLD) ORCID: 0000-0001-6545-1003
• Schrama Johan W., Wageningen University and Research Centre (NLD)
• Verreth Johan A.J., Wageningen Institute of Animal Sciences (NLD)
• Phillips Michael J., WorldFish (MYS)
• Verdegem Marc C.J., Wageningen Institute of Animal Sciences (NLD) - auteur correspondant

Source : Cirad-Agritrop (https://agritrop.cirad.fr/605210/)

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