| dc.description.abstract | With the expanding aquaculture activity, high quality ingredients for fish feeding are
required. In order to prevent the risk of depending on fish meal, research institutions and the
industry itself, have conducted studies to reduce the dependence of fish meal increasing the
nutritional value of alternative feedstuffs. The objective of the study was to evaluate different
methods of inactivation of antinutritional compounds on nutrient availability of plant protein
sources for catfish. The work was divided into three parts: removal of antinutrients, growth
trial, and digestibility experiment. In the first part, different chemical treatments for removal
of phytic acid, total phenols and tannins in canola, soybean and sunflower meals were tested.
The treatments were: acidified water (pH 1.0); ethanol PA + methanol PA; acidified ethanol
PA (pH 1.0); ethanol + water PA 70:30 pH 1.0; acidified water + ethanol PA, used
separatelly. Washing with pH 1,0 water, followed by washing in ethanol PA was the best
alternative for removal of phytic acid, phenols and tannins of canola, sunflower and soybean
meal. In the growth experiment were evaluated growth performance, body composition,
biochemical parameters, enzymatic profile and intestinal morphometry of juvenile catfish fed
with plant ingredients, treated or not treated for removal of antinutrients. Treatments were:
control diet, with fish meal as only protein source (CON); replacement of 30% of fishmeal
protein by untreated soybean meal (SNT), canola meal (CNT) and sunflower meal (GNT) or
the same ingredients submitted to treatment: (ST), (CT) and (GT) (soybean, canola and
sunflower, respectively). The treatment is effective, with the exception of phytic acid in
soybean meal. ST and CT can replace 30% of fish meal protein, without affecting the growth
of animals. There is no difference in the performance of fish fed CT compared to CNT, and
GT compared to GNT. For soybean meal, there is improvement in the nutritional value after
treatment. The biochemical changes do not appear to be linked to the antinutritional factors.
There is no interference of the treatment on the enzymatic activity of silver catfish. Fish fed
with untreated ingredients showed enlargement in the thickness of the muscle layer in the
intestinal epithelium. The number of villi is higher in fish fed with treated ingredients. There
is an increase in the thickness of the lamina propria of the villi in fish fed with the untreated
ingredients. In the digestibility experiment, were evaluated the apparent digestibility
coefficients (ADCs) of plant ingredients, submitted or not to chemical treatment to remove
antinutritional factors in diets for jundiá. The ADC for crude protein was higher in ST,
compared to CT and CNT, but did not differ from the others. GNT, GT and CNT showed the
lowest ADC for organic matter. The removal of antinutrients do not affect the ADC of crude
protein, dry matter and organic matter in soybean and sunflower meal. For canola meal,
removing antinutritional factors improve dry matter digestibility. In addition, besides the
antinutrients, special care must be taken to concentration or removal of other nutrients when
using chemical treatments, otherwise the nutritional value of the ingredient can be affected. | |
