F. P. Costa

Fatty Acid Profile of Eggs of Semi-Heavy Layers Fed Feeds containing Linseed Oil

The incorporation of polyunsaturated fatty acids in chicken eggs by adding oils to the diets has been extensively studied. This experiment aimed at evaluating possible changes in the fatty acid profile of the eggs of layers fed diets supplemented with linseed and soybean oils. The experiment was performed using 192 29 week-old laying hens, distributed in a completely randomized design, into six treatments with four replicates of eight birds each. Treatments consisted of a control diet (no vegetable oil) and diets including 2% of vegetable oil. Linseed oil replaced 0, 25, 50, 75, and 100% soybean oil in the diets, corresponding to 0.0, 0.5, 1.0, 1.5, and 2.0% of linseed oil in the diet. A pool of two egg yolks from each treatment was submitted to lipid extraction and fatty acid methylation, and subsequent gas chromatography (GC) analysis to detect seven fatty acids. Saturated (myristic and palmitic) fatty acids concentration was affected by lipid dietary source, with the lowest concentration in birds were fed feeds containing linseed oil. Polyunsaturated fatty acids (PUFA) concentration in the eggs was influenced by different levels of linseed oil inclusion. Linoleic acid egg content increased when linseed oil was used on diet as compared to the control diet. Linseed oil was considered an excellent source of linolenic acid incorporation in the eggs.

Corn and soybean meal metabolizable energy with the addition of exogenous enzymes for poultry

Two metabolism assays were carried out to determine corn and soybean meal metabolizable energy when enzymes were added. In the first trial, 35 cockerels per studied feedstuff (corn and soybean meal) were distributed in a completely randomized experimental design with four treatments of seven replicates of one bird each. The evaluated treatments were: ingredient (corn and soybean meal) with no enzyme addition, with the addition of an enzyme complex (xylanase, amylase, protease - XAP), xylanase, or phytase. Precise feeding method was used to determine true metabolizable energy corrected for nitrogen balance (TMEn). The use of enzymes did not result in any differences (p>0.05) in soybean meal TMEn, but phytase improved corn TMEn in 2.3% (p=0.004). In the second trial, 280 seven-day-old broiler chicks were distributed in a completely randomized experimental design with seven treatments of five replicates of eight birds each. Treatments consisted of corn with no enzyme addition or with the addition of amylase, xylanase, phytase, XAP complex, XAP+phytase combination, or xylanase/ pectinase/β-glucanase complex (XPBG). Corn was supplemented with macro and trace minerals. Total excreta collection was used to determine apparent metabolizable energy corrected for nitrogen balance (AMEn). Differences were observed (p=0.08) in AMEn and dry matter metabolizability coefficient (p=0.03). The combination of the XAP complex with phytase promoted a 2.11% increase in corn AMEn values, and the remaining enzymes allowed increased between 0.86% and 1.66%.

Requirements of digestible methionine + cystine for broiler chickens at 1 to 42 days of age

The objective of this work was to estimate requirements of digestible methionine + cystine for broiler chickens from 1 to 42 days of age. It was carried out four experiments for each one of the following phases: pre-initial, initial, growing and final. The birds were distributed in a completely randomized experimental design, with six treatments and six replicates. Treatments consisted of a basal feed for each phase, deficient in digestible methionine + cystine and supplemented with DL-methionine to supply six levels of digestible methionine + cystine, resulting in different digestible methionine + cystine:digestible lysine ratios. In the pre-initial phase, levels of digestible methionine + cystine did not influence feed intake and feed conversion. However, weight gain responded in a quadratic way. In the initial phase, levels of digestible methionine + cystine had decreasing linear effect on feed intake whereas weight gain and feed conversion were influenced in a quadratic manner. In the growth and final phases, feed intake was not influenced by levels of digestible methionine + cystine, but weight gain and feed conversion presented quadratic response. The levels of 0.873; 0.755; 0.748 and 0.661% of digestible methionine + cystine in the diet or the daily intake of 183; 575; 1,104 and 1,212 mg of digestible methionine + cystine are recommended for the pre-initial, initial, growth and final phases, respectively, which corresponds to the ratios of 71; 70; 76 and 72% of digestible methionine + cystine to digestible lysine.