Nucleotides, β-glucans, ascorbic acid, α-tocoferol, and different concentrations of a vitamin-mineral premix promote growth of Nile tilapia juveniles

ABSTRACT Feed additives, such as β-glucans, nucleotides, ascorbic acid (vitamin C), and α-tocopherol (vitamin E) can improve fish immunity and contribute to enhanced zootechnical performance of the fish. This study aimed to evaluate the effect of different concentrations of vitamin- mineral premix with or without the inclusion of an immunostimulant boost (β-glucans, nucleotides and vitamins C and E) on the zootechnical performance, hemato-immunological parameters, histological changes, and survival of Nile tilapia juveniles. To this end, isocaloric and isoproteic diets were prepared with three different concentrations of vitamin-mineral premix (1.0, 1.5, and 2.0 kg ton-1); additionally, the effects of 4% immunostimulant boost in the diet were examined considering six diets (without the immunostimulant boost: 0.1%, 0.15%, and 0.2%, and with the immunostimulant boost: 0.1% I, 0.15% I, and 0.2% I). We used 24 experimental units, each including 15 fish. Nile tilapia juveniles (1.88 g±0.25) were fed for 50 d with supplemented diets. Further, zootechnical indexes; histological changes in the liver, spleen, and intestine; intestinal morphology; and hemato-immunological parameters were evaluated. The fish that received supplementation showed higher zootechnical values, compared to those that did not receive the supplementation of immunostimulant reinforcement. Weight gain (30.45g±3.06), daily weight gain (0.60g±0.06), final weight (32.41g±3.15) and feed conversion (0.95±0.06) were higher in tilapia fed with an inclusion concentration of 0.2%. Hematological parameters were not affected by either the pre-mix concentrations or the booster of the immunostimulant. There was an increase in the number of intestinal folds, length of the fold, total area and number of goblet cells in the group supplemented with immunostimulant reinforcement. Supplementation with the immunostimulant promoted growth and improved intestinal morphology and immunological parameters of Nile tilapia juveniles

Apparent digestibility of ingredients in diets for Salminus brasiliensis Digestibilidade aparente de ingredientes em dietas para Salminus brasiliensis

The objective of this work was to determine the nutritional value of different protein sources for "dourado" (Salminus brasiliensis). Thirty juveniles per group (33.51&plusmn;1.4 g) were hand fed on a reference diet (70%) added of tested ingredients (30%) and chromium oxide III (0.1%). Apparent digestibility coefficients of the gross energy (ADC GE), crude protein (ADC CP) and amino acids of the tested ingredients were evaluated. Corn gluten meal yielded the best results for ADC GE and ADC CP (95.7 and 96.9%, respectively) amongst plant ingredients. Spray-dried blood meal yielded the best values of ADC GE and ADC CP amongst animal ingredients (94.1 and 96.3%, respectively). Wheat bran yielded poorest ADCs coefficients (77 for ADC GE and 88.2% for ADC CP).<br>O objetivo deste trabalho foi determinar o valor nutricional de diferentes fontes protéicas para o Dourado (Salminus brasiliensis). Trinta juvenis por grupo (33,51&plusmn;1,4 g) foram alimentados ad libitum com ração referência (70%) mais ingredientes-teste (30%) e marcador de óxido de cromo III (0,1%). Foram determinados os coeficientes de digestibilidade aparente da energia bruta (CDA EB), proteína bruta (CDA PB) e aminoácidos. Entre os ingredientes de origem vegetal, a glutenose apresentou os melhores resultados para CDA EB e CDA PB (95,7 e 96,9%, respectivamente). A farinha de sangue se destacou entre os ingredientes de origem animal (94,1 e 96,3%, respectivamente). O farelo de trigo apresentou menor digestibilidade entre todos, 77% para CDA EB e 88,2% para CDA PB