Due to the ban of antibiotics across the world there is pressure in finding alternative feed
additives that can be used for food animals. The aim of this study was to determine the effect of
butyric acid (Novyrate C) and monoglyceride (FRA®C12), with and without the addition of
antibiotics (Zinc Bacitracin 15%) on the performance and gut health of broiler chickens. The study
was conducted in an environmentally controlled commercial broiler house. The house contained
ninety-six pens in total, divided into two rows consisting of forty-eight pens each over the length of
the house. A total of two thousand three hundred and four male Ross 308 broiler birds were randomly
distributed throughout the pens, 24 birds per pen at a stocking density of 22 kg/m2. All the birds
received a typical South African maize-soya based diet throughout the trial. Dietary treatment
combinations were implemented in a 3-phase feeding programme: Starter (0 to 14 d), Grower (14 to
28 d) and Finisher (28 to 35 d). This study was conducted using eight different dietary treatments.
Treatment 1 was the positive control (Zinc Bacitracin 15% at 0.5 g/kg) and treatment 2 was the
negative control (without the Zinc Bacitracin). Treatments 3, 4 and 5 consisted of Zinc Bacitracin
together with either butyric acid (1 g/kg for starter, 0.75 g/kg for grower and 0.25 g/kg for finisher
phase), mono-glyceride (1 g/kg) or a combination of the test products (butyric acid and
monoglyceride). Treatments 6, 7 and 8 were the same as 3, 4 and 5 without the Zinc Bacitracin. Each
treatment was repeated once within a block, resulting in 12 replications per treatment. The birds had
ad libitum access to water and feed during the duration of the trial.
A weekly numerical difference was recorded for body weight (BW), feed intake (FI) and feed
conversion ratio (FCR). Two chicks per pen were sacrificed at the ages 20 and 33 days and duodenum,
jejunum and ileum samples were sectioned from the gut. Results showed that growth was not
significantly different between the treatments.The feed intake showed no significant difference either,
but the birds that were not supplemented with the Zinc Bacitracin showed a lower FI (3747 g)
compared to the group with Zinc Bacitracin inclusion (3767 g) at 35 days of age. The group of birds
supplemented with Zinc Bacitracin resulted in a significantly lower FCR (P < 0.05) compared to the
group without AGP at 7 days of age. The cumulative FCR of birds supplemented with both butyric
acid and monoglycerides without the Zinc Bacitracin was significantly lower (1.47) compared to the
same group with Zinc Bacitracin (1.51) from 0-35 days (P < 0.05).
The viscera and wing weights expressed as a percentage of the carcass weight were
significantly lower for birds that were supplemented with Zinc Bacitracin compared to the group of
birds without AGP (P < 0.05), but no significant differences were reported for the thighs, drumsticks
and breast weights relative to the carcass weight (P < 0.05) at 35 days of age. The supplementation of
butyric acid, monoglycerides and their combination without AGP resulted in a significantly longer
villi length in the duodenum, jejunum and ileum at 20 and 33 days. The combination of the two
products resulted thus in a lower FI, FCR and increased villi height. The recommendation will be to
use the products together as an alternative for antibiotic growth promoters in broiler feed.
Dissertation (MSc (Agric))--University of Pretoria, 2019.