Valquíria Cação Cruz-Polycarpo

1. The effect of microencapsulated and uncoated butyric acid as an alternative to antibiotics on performance, intestinal morphology and regeneration of intestinal mucosa was studied in birds experimentally infected with Eimeria spp. 1 to 42 d-old. 2. A total of 1,320 male Cobb® broiler chicks were allocated to one of five treatments in a completely randomised design, comprising a negative control, uncoated butyric acid (UA), microencapsulated butyric acid (MA), combined U + M butyric acid and a positive control (antibiotic+anticoccidial) in six replications. At 16 d-old, the birds were inoculated orally with 0.5 ml of a solution containing an Eimeria spp. pool. 3. At 21 d of age, the birds receiving butyric acid alone had higher body weight gain (BWG) and feed intake (FI) compared to those supplemented with the blend of acids. For the total rearing period, in all variables, the positive control performed best (P < 0.001). 4. At 14 d of age, birds that received diets containing UA had a deeper crypt depth in the jejunum than those fed diets containing microencapsulated acid (P = 0.0194). At 21 d of age, the birds fed the acids had higher villi (P = 0.0058) in the duodenum, compared to the negative control group. 5. Supplementation with microencapsulated acid contributed to the intestinal health and recovery of post-challenge birds, but did not result in improvements in performance.

This study aimed to evaluate the effect of isolated or combined citric and benzoic acids added to the diets of broiler chickens on performance, allometry of the digestive system organs, intestinal pH and quantity of microorganisms in the jejunum. A total of 840 male Cobb broiler chicks were utilized, distributed in a complete random design in 2 × 2 factorial scheme, supplemented or not with citric acid, and sodium benzoate, with seven replications. At 14 days old, 1mL of a solution containing 1 × 105 sporulated oocysts of Eimeria acervulina per bird was inoculated orally. There was no effect of the acids on the broiler’s performance in the 1 to 21-day period. In the total period (1 to 42 days), the broilers fed with a blend of citric and benzoic acid presented greater feed intake, without increment in weight gain. The data of allometry of the digestive system organs and the jejunal pH values were not influenced by the treatments. The citric acid increased the bacterial quantity of gram-positive coccus and total anaerobes in the jejunum. Under the conditions of the present study, we conclude that the citric and benzoic acids, isolated or combined, do not benefit the nutrition of broilers challenged with E. acervulina.

The objective of this research was to evaluate the nitrogen-corrected apparent metabolizable energy (AMEn) balance of the following lipid sources: soybean oil, sunflower oil, linseed oil, and fish oil. Two hundred eighty 24-wk-old laying hens of the Hysex White were used. The experimental diets consisted of a basal diet (reference group), basal diet + 10% soybean oil addition (group 1), basal diet + 10% sunflower oil addition (group 2), basal diet + 10% linseed oil addition (group 3), and basal diet + 10% fish oil addition (group 4), distributed in a completely randomized design with seven replicates and eight birds per experimental unit. The metabolic assay was performed by the total excreta collection method. The AMEn values found in the natural material were 9 334 kcal kg⁻¹ for soybean oil, 10 533 kcal kg⁻¹ for sunflower oil, 10 928 kcal kg⁻¹ for linseed oil, and 9 005 kcal kg⁻¹ for fish oil. The AMEn were different among the lipid sources. Sunflower oil and linseed oil had higher AMEn compared with soybean oil and fish oil (P < 0.05). The AMEn of the lipid sources of plant origin had higher values than the gross energy. The fatty acid profile of each lipid source was presented in this work. Thus, it is important to have individual nutritional information for each type of oil for laying hens, making it possible to formulate more appropriate and accurate feed.

The objective of this study was to evaluate lactic and butyric acids as alternatives to avilamycin as growth promot­ers on the immune response of broilers vaccinated against Newcastle disease. Seventy broilers were distributed in a completely randomized design using a 2×2+1 factorial arrangement: presence or absence of lactic acid and butyric acid plus a control treatment with the inclusion of avilamycin, with seven replicates and two birds per experimental unit. Birds were vaccinated against Newcastle disease at 14 days of age. Prior to vaccination (14 days), at 21 and 35 days, blood samples were collected to detect and quantify antibodies against Newcastle disease virus. At 14 and 21 days, there was no significant effect of treatments on antibody titers. At 35 days, the combination of lactic and butyric acids presented a synergistic effect on the immune response of the birds, provid­ing a higher amount of antibody titers compared to the other treatments. The combined effect of lactic and butyric acids improved the immune response of broilers vaccinated against Newcastle disease at 35 days of age, representing a viable alternative to avilamycin.

This study aimed to evaluate the effect of probiotics on performance, intestinal morphology and carcass characteristics of broiler chickens housed on lower or higher environmental challenge. Three hundred male Cobb chicks were distributed into four groups in completely randomised design with treatments arranged in a 2 x 2 factorial scheme to evaluate effects of two diets (with or without probiotics) and two environmental conditions (lower or higher challenge), totaling four treatments with five replications with 15 birds per box. Probiotics were added on diets and were composed of Lactobacillus acidophilus, Bacillus subtilis, Bifidobacterium bifidum and Enterococcus faecium. The environment with lower challenge was made up of new wood shavings used as litter, low bird density (8 birds/m²) and daily-cleaned bell drinkers. The environment with higher challenge was made up of re-used wood shavings used as litter (after three broods of broilers), bird density of 16 birds/m² with bell drinkers cleaned every two days. No significant interaction between diet and environmental challenge was found for any of the variables evaluated. Performance, slaughterhouse variables and chemical carcass composition were not affected by the use of probiotics. Chicks receiving diets without probiotics had lower intestinal crypt depth (267.1 vs. 316.6 pm, P=0.0068). Birds raised in the environment with higher challenge decreased feed intake (4,660 vs 5,020 g, P=0.0422), weight gain (2,610 vs 2,810 g, P= 0.0054), drumstick and thigh yield (21.98 vs 24.14 %, P=0.0354), and increased crypt depth (325.2 vs 258.5 pm P=0.0009). In conclusion, the probiotic does not promote satisfactory improvements, regardless of the environmental challenge.

The objective was to evaluate the performance, relative organ weight, morphometry, intestinal length and pancreatic enzyme activity of broilers receiving neonatal supplementation. A total of 900 Cobb 500 broiler chicks was housed in 30 boxes of 2.5 m². The treatments were divided in a completely randomized design with six replications, and consisted of five inclusion levels (0.0, 2.5, 5.0, 7.5 and 10 grams per bird). The supplement used was based of amino acids, vitamins and minerals, which was provided on the ration on the first day in the housing. Statistical analysis was performed using SAS (2008) and when significant broken down using a polynomial regression. Due to the inclusion of the neonatal supplement in the period from one to seven and one to 21 days of age, the feed intake presented a linear effect and the weight gain, a quadratic effect. The relative weights of the gizzard and liver showed a quadratic effect, and the inclusions of 4.18 and 3.41 grams/bird provided the lowest weights, respectively. The jejunum villi height decreased with supplementation as well as the activity of pancreatic lipase. It can be concluded that neonatal supplementation benefited the performance of birds up to 21 days of age.

This study evaluated the effect of multienzyme complexes (EC1 and EC2) in low nutritional density diets on performance and economic viability of broilers. A total of 840 day-old chicks were assigned to 7 treatments, distributed in a completely randomized design: (1) PC: positive control, basal diet formulated to meet nutritional requirements; (2) NC1: negative control, reduced energy and nutrient density diet without enzymes; (3) NC1+EC1; (4) NC2: negative control, diet formulated with 7% over-estimated crude protein and amino acids of soybean meal without enzymes; (5) NC2+EC2; (6) NC3: negative control, reduced energy and nutrient density diet and over-estimation of crude protein and amino acids of soybean meal; (7) NC3+EC1+EC2. Feeding NC1 or NC3 impaired feed conversion ratio at 7, 21 and 42 days, and NC2 at 21 days. Inclusion of EC2 in NC2 diet improved feed conversion ratio and kept it similar to basal diets from 1 to 21 days. Association of EC1 with EC2 in NC3 diet did not improve performance. In summary, inclusion of EC2 in diets with reduced nutrient density keep feed conversion ratio similar to basal diets from 1 to 21 days but does not improve performance of broiler chicken from 1 to 42 days post-hatch.