Partial or total replacement of fish meal by local agricultural by-products in diets of juvenile African catfish (Clarias gariepinus): growth performance, feed efficiency and digestibility

Abstract

The study was undertaken to evaluate the growth performance and feed utilization of African catfish, Clarias gariepinus, fed six diets (D) in which fishmeal (FM) was gradually replaced by a mixture of local plant by-products. In diets 1 and 2, FM (250 g kg )1 ) was replaced by sunflower oil cake (SFOC). In diets 3 and 4, FM (250 and 150 g kg )1 , respectively) was replaced by SFOC and bean meal (BM) while FM was totally substituted by a mixture of groundnut oil cake (GOC), BM and SFOC in diets 5 and 6. Sunflower oil cake was cooked, soaked or dehulled in order to determine the appropriate processing techniques for improving the SFOC nutritive value and to evaluate the apparent digestibility coefficient (ADC) values of the alternative diets. No significant differences were observed for daily feed intake, weight gain, specific growth rate (SGR) and feed efficiency (FE) among fish fed D1, D2, D3 (250 g kg )1 FM), D4 (150 g kg )1 FM) and D6 (0 g kg )1 FM). The highest SGR (3.2% per day) and FE (1.2) were achieved in fish fed D3, and the lowest in fish fed D5 (0% FM), suggesting a maximum acceptable dietary concentration of hulled SFOC below 250 g kg )1 in African catfish juveniles. Protein efficiency ratio ranged from 2.2 to 3.2 for all dietary treatments and was positively influenced by FM inclusion. African catfish were able to digest plant protein very efficiently in all diets tested. ADC of protein ranged from 88.6 to 89.5%, while ADC of energy was relatively low for diets containing hulled sunflower oilcake (71-74%) and high when sunflower oilcake was dehulled (78.6-81.3%). Similarly, ADC of dry matter was higher when sunflower was dehulled (72.1%) when compared with crude SFOC (60.5%). Soaking increased ADC values for neutral detergent fibre (NDF), dry matter, energy, protein and amino acids (AA). There were no significant differences in protein ADCs (88-90%) with increased levels of dietary vegetable ingredients. Both soaking and dehulling of sunflower before incorporation helped in the reduction of NDF, antitrypsin and tannins. Digestibility of all AA was generally high, greater than 90% for both indispensable and non-indispensable AA. Based on the data obtained, it was possible to totally replace menhaden fish meal with a mixture of vegetable proteins (72% of total dietary protein) when diets contained a relatively low percentage of animal protein (28% based on blood meal and chicken viscera meal) without negative effects. KEY WORDS

Extração de antinutrientes e aumento da qualidade nutricional dos farelos de girassol, canola e soja para alimentação de peixes

“…De acordo com o farelo, tipo de tratamento e antinutriente em questão, foram observados efeitos positivos e negativos. Os teores de antinutrientes encontrados nos farelos não tratados mostraram-se semelhantes aos encontrados por outros pesquisadores (BELL, 1993;GATLIN III et al, 2007;NYINA-WAMWIZA et al, 2010;LOMASCOLO et al, 2012 Observando-se os resultados, fi ca evidenciada a necessidade de se conhecer detalhadamente a composição da matéria-prima a ser tratada, para que seja feita a correta escolha do tipo de solvente. Os métodos de extração ou inativação podem ser efi cientes para a retirada de um ou vários antinutrientes, mas podem, ao mesmo tempo, comprometer a qualidade nutricional do farelo.…”

Docosahexaenoic acid in Arctic charr (Salvelinus alpinus): The importance of dietary supply and physiological response during the entire growth period

“…affect digestive functions by increasing intestinal flow rates (Lienner 1980, Krogdahl 1989Nyina-Wamwiza et al 2010), which may reduce the retention of dietary nutrients (Krogdahl 1989). This suggested that a 2-fold increase in pumpkin kernel cake in the present study may have affected nutrient absorption, resulting in the lower growth rates of fish fed dietary treatments F2, F3 and F4.…”

Growth Performance, Feed Utilization and Body Composition of Clarias gariepinus (Burchell 1822) Fed Marine Fish Viscera-based-diet in Earthen Ponds

“…Total carbohydrates was estimated by subtracting crude protein, lipid and ash values from 100. Gross energy [24].…”

“…The economically feasible catfish farming can be achieved when it is based on costeffective feed compound of locally available agricultural by-products [17,22,23]. Many alternatives resources such as feather meal [19], meat and bone meal, hydrolyzed feather meal, fleshings-meal and blood meal [24,25], dried fermented fish by-product silage [6], poultry silage [26], shrimp head waste meal [27,28], poultry by-product meal [2,29], skate meal and sablefish viscera meal [30] have been tried to replace fish meal either partially or fully, but even these meals of various animal sources are not sufficient to meet the growing demands of fish raising industry.…”