Digestibilidade aparente de nutrientes, energia e aminoácidos de tortas de pinhão‑manso atóxica e destoxificada para tilápia‑do‑nilo

The objective of this work was to evaluate the apparent digestibility coefficients of nutrients, energy, and amino acids of nontoxic and detoxified physic nut cakes treated with solvent plus posterior extrusion, for Nile tilapia. The apparent digestibility coefficients of crude protein and gross energy were higher for detoxified than for nontoxic physic nut cake. However, the apparent digestibility coefficient of ether extract of the nontoxic physic nut cake was higher than that of the detoxified one. The apparent digestibility coefficient of amino acids of both feed ingredients was superior to 80%, except for glycine, for the nontoxic psychic nut cake, and for threonine, for the detoxified one. Nontoxic and detoxified physic nut cakes show apparent digestibility coefficient values equivalent to those of the other evaluated oilseeds and potential for inclusion in Nile tilapia diets.O objetivo deste trabalho foi avaliar os coeficientes de digestibilidade aparente de nutrientes, energia e aminoácidos de tortas de pinhão‑manso atóxica e destoxificada tratadas com solvente e posterior extrusão, para tilápia‑do‑nilo. Os coeficientes de digestibilidade aparente da proteína bruta e da energia bruta foram maiores para a torta destoxificada do que para a atóxica. No entanto, o coeficiente de digestibilidade aparente do extrato etéreo da torta atóxica foi superior ao da destoxificada. O coeficiente de digestibilidade aparente dos aminoácidos dos dois alimentos foi maior que 80%, exceto para glicina, para a torta atóxica, e para treonina, para a destoxificada. Tanto a torta atóxica quanto a destoxificada de pinhão‑manso apresentam valores similares aos das outras oleaginosas avaliadas e potencial para utilização em dietas para tilápia‑do‑nilo

Stocking density and feeding rate of South American catfish reared in net cages

O objetivo deste trabalho foi avaliar o efeito de diferentes densidades de estocagem e frequências alimentares sobre a resposta zootécnica e metabólica, e sobre a composição de peixe inteiro e de filé de juvenis de jundiá (Rhamdia quelen) cultivados em tanques‑rede durante 60 dias. Foram utilizados 1.200 juvenis de jundiá (57,48±3,34 g e 17,86±0,36 cm). Os peixes foram distribuídos em delineamento inteiramente casualizado, em arranjo fatorial 2×2, à densidade de 50 e 150 peixes m‑3 e frequência alimentar de uma ou duas vezes ao dia. Tanto as densidades de estocagem quanto o manejo alimentar não influenciaram o desempenho nem os parâmetros metabólicos. No entanto, a interação entre a menor densidade e a maior frequência alimentarresultou em menor teor lipídico nos filés. Como ambos os fatores testados não interferiram no desempenho zootécnico, pode-se sugerir como melhor densidade a de 150 peixes m‑³, com frequência de arraçoamento de uma vez ao dia.The objective of this work was to evaluate the effect of different stocking densities and feeding frequencies on the zootechnical and metabolic response and on the whole fish and fillet composition of juvenile South American catfish (Rhamdia quelen) cultured in net cages for 60 days. One thousand and two hundred juvenile catfish (57,48±3,34 g and 17,86±0,36 cm) were used. Fish were distributed in a completely randomized design, with a 2×2 factorial arrangement, at 50 and 150 fish m‑3 and feeding frequency once or twice a day. Both stocking density and feeding influenced neither the performance, nor the metabolic parameters. However, the interaction between the lowest density and the highest feeding frequency resulted in the lowest lipid content in the fillets. As both tested factors did not affect the growth performance, 150 fish m‑3 can be suggested as the best density together with a once‑a‑day feeding frequency

Challenges for efficient use of phytase in fish nutrition

Phosphorus is stored in plants majorly in the form of phytic acid (IP6), which represents 50–80% of the total phosphorus present in the vegetable ingredients. As it is indigestible by nonruminant animals and remains negatively charged in the physiologic pH, it binds to a large variety of nutrients, mainly cations, which are discarded via feces. This leads to the addition of available phosphorus, which increases the cost and environmental problems. Therefore, the utilization of phytase helps to break IP6 and increases the use of the unavailable phosphorus. Phytase is successfully used in poultry and pigs feeding, whereas for fish, the results are ambiguous. Phytase acts in an optimum range of temperature and pH and denatures when subjected to extremes conditions. Thus, feed processing (extrusion) and the anatomical and physiological conditions of the fish species challenge its molecular integrity and activity. Hence, understanding the main aspects based on the results obtained by the use of phytase in fish feeding leads to optimal utilization of this enzyme due to its ideal activity and the challenges induced by processing and the fish species

Concentrado proteico de vísceras de surubim híbrido em dietas para cachara

The current study evaluated the growth performance and the haematological profile of barred sorubim fed with levels of hybrid sorubim viscera protein concentrate (0.0; 5.0; 10.0 e 15.0%) in isoprotein and isoenergetic diets. Eighty fish with an average initial weight of 39.8 ± 0.28 g and an average initial length of 19.92 ± 0.25 cm were distributed in 16 aquaria of 60 L, with recirculation system and temperature control, during 35 days. The experimental design was completely randomized with four treatments and four replications. For the growth performance assay were analyzed the follows variables: weight gain (WG), feed consumption (FC), apparent feed conversion ratio (AFCR) and protein efficiency ratio (PER). Furthermore, the hemogram were assessed on the treated fish with levels of protein concentrate. It was observed no significant difference (P>0.05) for all the parameters evaluated. It was concluded that the protein concentrate from hybrid sorubim viscera can be included up to 15% in diets for barred sorubim juveniles without negative response on the performance and health

Fontes protéicas vegetais na alimentação da carpa húngara Plant protein sources on common carp feeding

A substituição parcial da farinha de carne suína por farelos vegetais em dietas para juvenis de carpa húngara (Cyprinus carpio) foi avaliada em cinco dietas experimentais: um controle (farinha de carne suína (FCS) como fonte protéica) e quatro dietas vegetais: farelo de soja (FS), farelo de canola (FC), farelo de girassol (FG) ou farelo de linhaça (FL), substituindo 50% da proteína proveniente da FCS. 195 juvenis (43,4&plusmn;0,4g) foram alimentados duas vezes ao dia (9 e 15 horas) durante 71 dias. Ao final do experimento, maior peso (205,69g), ganho em peso (2,29g dia-1), taxa de crescimento específico (2,2% dia-1) e conversão alimentar (1,74) foram obtidos nas dietas com FCS, seguido dos tratamentos FC e FS que não diferiram entre si. Os peixes alimentados com FCS, FG e FS apresentaram maior gordura corporal. A dieta FL apresentou piores resultados de desempenho, coeficiente de retenção protéica, deposição de proteína e gordura corporal e no filé. Pode-se concluir que a dieta à base de farinha de carne suína proporciona maior crescimento e deposição de proteína em juvenis de carpa húngara, comparada às dietas com farelos vegetais; os parâmetros de carcaça (rendimentos e índices digestivos) não são afetados pelas fontes protéicas da dieta.<br>This study was conducted to evaluate the partial replacement of porcine meat meal by plant-protein meals in diets for common carp (Cyprinus carpio). Five experimental diets were evaluated: control (FCS), only porcine meat meal as protein source, and four plant-based diets: soybean meal (FS), canola meal (FC), sunflower meal (FG) or linseed meal (FL) replacing 50% of protein from porcine meat meal. Juveniles (195, 43.4&plusmn;0.4g) were fed twice daily (9:00 am and 03:00pm) for 71 days. At the end of the trial, the best weight (205,69g), weight gain (2,29g day-1), specific growth rate (2,2% day-1) and food conversion ratio (1,74) were obtained in FCS, followed by FC and FS, that did not differ among each other. Fish fed FCS, FG and FS showed higher body fat. The FL diet had the worst performance, protein retention coefficient, protein and fat deposition in whole body and fillet. It was concluded that a diet based on porcine meat meal provides higher growth and protein deposition in common carp juveniles, compared to diets with plant-protein meals; carcass parameters (carcass and fillet yield and digestive indices) are not affected by the dietary protein sources