Protein to energy ratios in goldfish (Carassius auratus) diets

Abstract

The optimal dietary digestible protein to energy ratio is critical for the success of fish farming. Considering that it provides the proper development of the animals, this study was undertaken to evaluate the effects of different dietary digestible protein to energy ratio in diets for goldfish fingerlings. Diets were formulated to contain 28.0, 35.0, 42.0 and 49.0% DP and 3,600 and 3,200 kcal/ kg. The growth parameters evaluated were daily weight gain (DWG), feed intake (FI), feed conversion ratio (FCR), protein efficiency ratio (PER), protein productive value (PPV) and energy retention ratio (ERR) and specific growth rate (SGR). Regardless FI, all the parameters were affected by protein and energy levels and interaction between both factors was observed. The second-order polynomial equation best fitted to the DWG, SGR, FCR, PER and ERR with estimated requirement values of 38.81, 38.85, 41.05, 41.80 and 39.39% DP, respectively, at the 3,200 kcal/kg. A second-order polynomial model was significant only for the ERR data at the 3,600 kcal/kg with an estimated requirement value of 36.45% DP. Generally, fish fed diets containing 3,200 kcal/kg had better growth performance than fish fed 3,600 kcal/kg (P<0.01), indicating a higher feed efficiency. A 3,200 kcal/kg diet seems to be the proper DE level for meeting goldfish requirement for highest weight gain. Based on this experimental condition, we recommend the use of DP levels between 38.0-40.0% in diets for goldfish with 3,200 kcal/kg or a dietary protein to energy ratio between 119-125 mg/ kcal DE.Index terms: Energy requirement, feed intake, growth protein requirement, ornamental fish. RESUMOA ótima relação energia/proteína é importante para o sucesso da piscicultura. Considerando que a mesma fornece o adequado desenvolvimento dos animais, este estudo foi realizado para avaliar a relação energia/proteína digestível ótima para alevinos de kinguio. Dietas foram formuladas para conter 28,0; 35,0; 42,0 e 49,0% PD e 3600 e 3200 kcal/kg. Foram avaliados: ganho de peso diário (GPD), consumo de ração aparente (CRA), conversão alimentar aparente (CAA), taxa de eficiência protéica (TEP), valor produtivo protéico (VPP), taxa de retenção de energia (TRE) e taxa de crescimento especifico (TCE). Com exceção do CRA, todos os parâmetros foram afetados pelos níveis de proteína e energia e interação entre os dois fatores foram observados. O modelo que melhor se ajustou aos parâmetros GPD, TCE, CAA, TEP e TRE foi o polinomial de segunda ordem com valores de exigência de 38,81; 38,85; 41,05; 41,80 e 39,39% DP, respectivamente, para o nível de 3200 kcal ED/kg. O modelo polinomial de segunda ordem foi significativo apenas para os dados de TRE no nível de 3600 kcal ED/kg, com valor de exigência 36,45% PD. Os peixes alimentados com dietas contendo 3200 kcal/kg apresentaram melhor desempenho de crescimento do que os alimentados com 3600 kcal/kg (P<0,01), indicando uma maior eficiência alimentar. 3200 kcal/kg ED parece ser o nível adequado encontrado para kinguio para maior ganho d...

Evaluation of five commercial diets used for fish feeding in Basra governorate, southern Iraq

“…PER values increased significantly with increasing of dietary protein in the diets up to 30%, then reduced significantly when the dietary protein level was increased to 46%. Similar results were reported in common carp fingerlings (Ahmad et al, 2012), goldfish fingerlings (Souto et al, 2013), Nile tilapia fingerlings (Eid et al, 2003) and Kutum fingerlings (Ebrahimi and Ouraji, 2012). Rice et al, (1994) mentioned that the PER values are reduced when protein levels in the feed are either insufficient or are in excess, optimum protein content in fish feeds is species specific and occurs when PER is maximized.…”

Effect of Lysine Supplementation in Commercial Feed on Energy Retention and Feed Conversion Ratio of Carp (Osphronemus gouramy)

“…Comparison between protein retention and energy must be optimal in order to stimulate growth. In fact, high energy intake can reduce protein consumption as an energy source (Souto et al, 2013).…”

Nutrition in ornamental aquaculture: the raise of anthropocentrism in aquaculture?

“…The greater part of feed ingredients currently used in ornamental aquaculture are the same as that used in conventional aquaculture, in fact, the main ingredient of ornamental fish feeds is fish meal (Tlusty 2002;Velasco-Santamar ıa & Corredor-Santamar ıa 2011). Moreover, it should be reminded that first ornamental fish farmed in the history were koi carp and goldfish, previously raised for conventional aquaculture (Balon 2004;Snellgrove & Alexander 2011;Souto et al 2013) and they were presumably fed with same kind of fish feeds, both for conventional than for ornamental purpose. Today, the situation has profoundly changed and in the market of ornamental aquaculture, there are several kinds of fish feeds, thus comprising different categories such as freshwater versus marine species, aquarium fish versus pond fish, carnivorous versus herbivorous, vertebrates versus invertebrates, monospecific versus multi-species, surface feeders fish versus bottom feeder fish.…”