Performance and economic analysis of the production of Nile tilapia submitted to different feeding management

Abstract

The productive performance and the variable cost of production were evaluated for different feeding strategies for tilapia during the production cycle. A sample of 2,000 juvenile tilapia was distributed (23.55 ± 2.38 g) into five treatments and with four repetitions as follows: C (feed consumption to apparent satiety), R20 (beginning feed restriction when fish reached an average weight of 20 g), R200 (beginning feed restriction when fish reached an average weight of 200 g), R400 (beginning feed restriction when fish reached an average weight of 400 g) and R600 (beginning feed restriction when fish reached an average weight of 600 g). The fish were given extruded commercial feed containing 34% crude protein until they reached a weight of 200 g, at which time they received feed containing 32% crude protein. Monthly biometrics were performed in order to determine the food restriction starting point, which was one day of restriction followed by six feeding days. The following parameters were evaluated: water quality, productive performance variables, the variable costs of production and excreted nitrogen. The results were subjected to analysis of variance, and the means were compared using Tukey's test (5% significance). No statistical differences were observed in final weight, weight gain, feed consumption, feed conversion or survival. The fish from the R20 treatment had the lowest variable cost of production (g fish -1 ) and the lowest nitrogen excretion into the water. This suggests that feed restriction from the early stages of life does not compromise the productive performance and contributes to reducing the variable costs and the quantity of nitrogen excreted into the environment. Thus, a one-day per week feed restriction strategy can be applied from the earliest stages of life without compromising the productive performance or body composition of Nile tilapia. This strategy can also reduce variable costs of production by means of reducing relative labour and feed costs. (23,55 ± 2,38 g) em cinco tratamentos e quatro repetições: C (consumo até a saciedade aparente), R20 (início da restrição quando peixes atingiam peso médio de 20 g), R200 (início da restrição quando peixes atingiam peso médio de 200 g), R400 (início da restrição quando peixes atingiam peso médio de 400 g) e R600 (início da restrição quando peixes atingiam peso médio de 600 g). Os peixes foram alimentados com ração comercial extrusada com 34% de proteína bruta até atingirem 200 g, quando passaram a receber ração contendo 32% de proteína bruta. Foram realizadas biometrias mensais para determinação do início da restrição alimentar, que foi de um dia de restrição seguido de seis dias de alimentação. Foram avaliados os parâmetros de qualidade da água, variáveis de desempenho produtivo, os custos variáveis de produção e o nitrogênio excretado. Os resultados obtidos foram submetidos à análise de variância e as médias foram comparadas pelo teste Tukey (5%). Não foram verificadas diferenças estatísticas no peso final, ganho de peso, consumo de...

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“…Correspondingly, hybrid tilapia juveniles (O. niloticus x O. aureus) deprived of feed 3 days per week presented poor growth compared to those deprived for 1 and 2 days, respectively (Abdel-Hakim et al, 2009). Poor compensatory growth in fish exposed to longer deprivation periods were also reported in Nile tilapia (Gao & Lee, 2012;Passinato et al, 2015), O. mossambicus (Christensesn & Mclean, 1998), and in other species such as Centropomus parallelus (Ribeiro & Tsuzuki, 2010) and Sparus aurata (Peres, Santos, & Oliva-Teles, 2011).…”

“…They further indicated that moderate feed deprivation regime (1, and 2 days per week) showed a significant reduction in feeding costs. Moreover, full compensatory growth was reported in Nile tilapia (Passinato et al, 2015;Cuvin-Aralar et al, 2012;Gao & Lee, 2012); Lates calcarifer (Tian & Qin, 2004) subjected to different feed restriction /refeeding regimes, respectively.…”

“…However, various studies suggested that compensatory growth in fish could be a result of low basal metabolism (Fu, Xie, & Cao, 2005), increased feed intake (hyperphagia) (Xie et al, 2001), or improved feed utilization indices such as FCR and FER (Foss et al, 2009;Adakli & Tasbozan, 2015) following period of starvation or intermitted feeding. Improved feed utilization parameters has been observed in many fish including hybrid tilapia (O. niloticus x O. aureus) (Abdel-Hakim et al, 2009), Nile tilapia (Passinato et al, 2015), and even in shellfish such as Fenneropenaeus chinesis (Zhang, Zhang, Li, & Gao, 2010) exposed to feed deprivation and refeeding regimes. Improvement in these parameters is attributed by an increase in digestive capacity of fish during refeeding period as reported by (Bolasina, Perez, and Yamashita, 2006).…”

“…Similarly, inconsistent results were documented in tilapia species such as complete compensation in Oreochromis niloticus (Cuvin-Aralar et al, 2012;Passinato et al, 2015), a limited capacity in hybrid tilapia (O. mossambicus x O. niloticus) (Wang, Cui, Yang, & Cai, 2000;Gabriel, Omoregie, Tjipute, Kukuri, & Shilombwelwa, 2017), and a lack of compensatory growth in Oreochromis niloticus (Gao, Wang, Hur, & Lee, 2015). Adequate information is required to explain these inconsistent findings between and among fish species reared under different experimental systems and feeding protocols.…”