Digestible threonine requirement in diets for tambatinga (♀Colossoma macropomum x ♂Piaractus brachypomus) fingerlings

Abstract

Cross breeding of native fish species is a technique to produce hybrids that can express higher weight gain and feed efficiency compared to the parental species. The digestible threonine requirement in diets for tambatinga fingerlings (Colossoma macropomum ♀ x Piaractus brachypomus ♂) was determined in this study. For this, 700 fingerlings with an average initial weight of 2.39 ±0.02 g and average final weight of 35.96 ±2.03 g were distributed in a completely randomized design consisting of six treatments (0.600, 0.800, 1.000, 1.200, 1.400, and 1.600% digestible threonine) and five replicates per treatment, with 20 fish per experimental unit. Diets were formulated by the “diet dilution” technique using the ideal protein concept. Performance, feed efficiency, body depositions of protein, ash and fat, and nitrogen retention efficiency of the fish were evaluated. The digestible threonine levels that optimized weight gain, specific growth rate, and feed conversion ratio were 1.40, 1.27 and 1.10%, respectively. Body deposition of fat was reduced in a quadratic manner (p<0.01), and the body depositions of protein and ash, together with the efficiency of nitrogen retention, were optimized by the digestible threonine level of 1.20; 1.33, and 0.82%, respectively. The recommended digestible threonine level in the diet for tambatinga fingerlings is 1.20 to 1.40% (0.40 and 0.47% Mcal DE-1) to obtain higher body deposition of protein and weight gain, respectively.

Lysine requirements of tambatinga (♀ Colossoma macropomum × ♂ Piaractus brachypomus ) fingerlings using different diet formulation techniques

“…Regarding the comparison of techniques, the equivalence of results in the main variables evaluated, in particular weight gain, feed conversion ratio and body protein deposition confirms the feasibility of using the dilution technique in the studies to determine amino acids requirements in fishes. This equivalence was also observed in a study with broilers (D'Mello, 1982;Siqueira et al, 2013) and corroborates the researches carried out white fishes by Bomfim et al (2020), Bomfim et al (2021), Liebert (2009) and Marchão et al (2020).…”

“…Tambatinga is a hybrid resulting from the crossing of two round fishes: ♀Colossoma macropomum (tambaqui) with ♂Piaractus brachypomum (pirapitinga). This hybrid stands out in Brazilian fish farming owing to its omnivorous feeding habits, has rapid growth, good carcass yield and adapts easily in the intensive production system (Bomfim et al, 2021;Guimarães & Martins, 2016;Welengane et al, 2019).…”

Digestible threonine requirement in tambaqui ( Colossoma macropomum ) diets: Growth, body deposition, haematology and metabolic variables

“…On the other hand, the reduction in body deposition in fish fed digestible Thr levels above the requirement has also been observed in Nile tilapia (Michelato et al, 2016) and tambatinga (Bomfim et al, 2021). These findings can be attributed to the extra energy expenditure for deamination, ammonia excretion of excess amino acids, antagonism of the absorption site and amino acid toxicity (Ahmed et al, 2004;Wu, 2013).…”

“…The best digestible Thr levels found in our study (10.40 and10.80 g kg diet −1 ) were slightly lower than those found by Firmo et al ( 2018), which can improve the manufacture of diets for larger tambaqui. In addition, other studies had reported beneficial effects for growth performance and feed efficiency when Thr was added to the diet, as verified in major carp (Ahmed et al, 2004), Indian catfish (Heteropneustes fossilis) (Ahmed, 2007), Nile tilapia (Bomfim et al, 2008;Michelato et al, 2016;Yue et al, 2014), Jian carp (Feng et al, 2013), grass carp (Gao et al, 2014), Indian major carp (Zehra & Khan, 2016) and tambatinga (Bomfim et al, 2021).…”

“…The increase in energy expenditure to catabolize excess amino acids reduces the amount of liquid energy (BFD) (Zehra & Khan, 2016) and the percentage of nitrogen retained (NRE) (Marchao et al, 2020). In addition, the effect of BAD is related to the use of minerals to form bone tissue and, consequently, to support muscle tissue (Bomfim et al, 2021). can reduce body protein synthesis, favouring fat deposition through amino acid catabolism (Abimorad et al, 2010), which would increase the excretion of nitrogenous compounds in water.…”