Browsing by Author "Tshonaphi, Caswell Sifiso."

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Effects of essential oil, probiotic, palm kernel fatty acid distillate, optigut, or sunflower whole seeds as alternatives to antibiotic growth promoters on broiler performance.
(2019) Tshonaphi, Caswell Sifiso.; Ciacciariello, Mariana.
The increasing consumer and legislation pressure to phase out the antibiotic growth promoters (AGPs) in the broiler industry has prompted researchers to find suitable alternatives to AGPs that will improve broiler performance at levels comparable to AGPs. There were three trials that were conducted in the present study. The aim of the first trial was to evaluate the effects of supplementing broiler diets with Oligo essential (essential oil) or AGPs on growth performance and caecal Clostridium perfringens (C. perfringens) counts of broilers from 0 to 33 days of age, reared in a commercial farm. A total of ten broiler houses were used for the trial. Five houses were designated for broilers receiving feed supplemented with AGPs and other five houses for broilers receiving feed supplemented with Oligo Essential. The houses were used as experimental units. The control houses (1, 2, 3, 4, and 5) were paired with trial houses (7, 8, 9, 10, and 11). The chicks placed in paired houses had the same parent flock age, were placed on the same day and also slaughtered at the same age. A total of 300 000 day old broiler chicks (Cobb 500) of mixed sex were used in the trial and the stocking density per house was 22.10 birds/m2. In the period of 0 to 33 days of age, it was observed that the broilers that were fed diets supplemented with Oligo Essential had a significantly poorer feed conversion ratio (FCR) and higher feed intake (FI) when compared to broilers that were fed diets containing AGPs. However, no effect of dietary treatment was seen on the body weight (BW). The caecal C. perfringens counts at 9 and 30 days of age were unaffected by dietary treatment. In conclusion, supplementing broiler diets with Oligo Essential had negative effects on broiler performance in the present study. In the second trial, the objective was to determine the effects of Lactobacillus based probiotic or AGPs on broiler performance in a commercial farm. A total of six broiler houses were used for the trial. Three houses were designated for broilers receiving feed supplemented with AGPs and other three houses for broilers receiving feed without AGPs, but all the day-old chicks were sprayed with Lactobacillus based probiotic at the hatchery. The dosing volume was 10ml per 100 chicks. The houses were used as experimental units. The control houses (1, 2, and 3) were paired with trial houses (4, 5, and 6). The chicks placed in paired houses had the same parent flock age, were placed on the same day and also slaughtered at the same age. A total of 180 000 day old broiler chicks (Cobb 500) of mixed sex were used in the trial and the stocking density per house was 20.80 birds/m2. It was noted that there was no significant difference in BW, FCR, FI and mortality between the treatments at 33 days of age. Therefore, it was concluded that the Lactobacillus based probiotic demonstrated feasibility of being a substitute for AGPs as the broiler performance was comparable to broilers that received diets supplemented with AGPs. In the third trial, the objective was to investigate the effects of Optigut, palm kernel fatty acid distillate and sunflower whole seeds on broiler performance, organs weights, intestinal length, digesta pH and caecal microbial profile. A total of 3360 Cobb 500 day old broiler chicks were randomly distributed into 48 pens. There were six dietary treatments for the trial: (i) Negative control with no AGPs; (ii) Negative control supplemented with AGPs; (iii) Negative control supplemented with Palm kernel fatty acid distillate at 2.5%; (iv) Negative control supplemented with Optigut at 0.4% in the starter, 0.2% in the grower and 0.1% in the finisher; (v) Negative control supplemented with Sunflower whole seeds at 4.0%; (vi) Negative control supplemented with Palm kernel fatty acid distillate (2.5%) and Sunflower whole seeds (4.0%). It was observed that there was no significant treatment effect on broiler performance parameters, organs weights, intestinal length, digesta pH and caecal microbial profile at 35 days of age. The results of the study suggest that the trial was conducted in a hygienic environment, therefore, it was recommended to conduct challenge studies to further investigate the effects of these alternatives to AGPs.