Browsing by Author "Pieterse, E."

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    The effect of porcine somatotropin (pST) and gender on production parameters and tissue yield of pigs slaughtered at 135 kg live weight
    (South African Society for Animal Science, 2009) Pieterse, E.; Swarts, I. C.; Hoffman, L. C.
    Eighteen F1 crossbred (commercial-type terminal crosses) pigs (boars, barrows and gilts) with an initial weight of 27.2 ± 2 kg were used to investigate the effect of porcine somatotropin (pST) administered for six weeks prior to slaughter on production parameters and tissue yield in the South African scenario. Pigs were grown to 135 kg live weight, which is heavier than the average weight at slaughter in South Africa of 80 - 100 kg. Porcine somatotropin had no significant effect on average daily gain or feed intake. However, pST administration caused a significant increase in feed conversion ratio (kg feed/kg gain) of treated boars, indicating that boars converted their feed less efficiently when treated with pST. This contradicts most of the findings in the literature. The effect of pST on the different carcass cuts was not significant, except for the percentage loin back, which was higher for pST-treated animals and percentage middle back of boars and barrows, which was slightly higher. No significant pST effects were found for live weight, carcass weight, % bone, % fat or % lean meat, but a significant increase in percentage skin was found.
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    Performance, water intake, carcass characteristics and intestinal histomorphology of broilers supplemented with phytase
    (South African Society for Animal Science, 2018-09-07) Van Emmenes, L.; Pieterse, E.; Hoffman, L. C.
    A 32-day experiment was conducted to study the effects of supplementation of phytase enzyme, Ronozyme® HiPhos (DSM Nutritional Products, Basel, Switzerland), on the production parameters, water intake, intestinal histomorphology, carcass characteristics and bone mineralization of broiler chickens. A total of 1920 one-day-old Cobb 500 broilers were randomly allocated to one of three treatments, each comprising eight replicate cages (eight replications per treatment) with 80 birds per cage. Dietary treatments were created using a standard commercial diet as the positive control (CON); reducing the nutrient content of the CON diet with values similar to the matrix values of 1500 FYT (phytase units) Ronozyme® HiPhos to create the negative control diet (NEG); and supplementing the NEG diet with 1500 FYT/kg Ronozyme HiPhos to create the phytase diet (HiPhos). Supplementation of the NEG diet with HiPhos significantly improved average daily gain (ADG), feed conversion ratio (FCR), bodyweight (BW) at slaughter and the European production efficiency factor (EPEF) of broilers compared with those in the NEG treatment group, but had no effect on total feed intake, water intake, villi height, crypt depth, dressing percentage, portion yields, pH of the meat or colour of the meat. Fat-free bone ash percentage and tibia breaking strength of broilers in the HiPhos treatment group were intermediate to broilers in the NEG and CON treatment groups. Results from the study proved that broilers could be supplemented with HiPhos phytase without detrimental effects on growth parameters, bone mineralization, carcass characteristics and water intake.
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    Safety assessment of antibiotic and probiotic feed additives for Gallus gallus domesticus
    (Nature Research, 2017) Neveling, D. P.; Van Emmenes, L.; Ahire, J. J.; Pieterse, E.; Smith, C.; Dicks, L. M. T.
    Antibiotics in feed select for resistant strains and is thus a threat to human health. In this study, the effect of a multi-strain probiotic and antibiotics on the growth and health of broilers was studied. Equal numbers of broilers received on a daily basis either a multi-strain probiotic or a combination of sulphadiazine, colistin and trimethoprim, whereas the control group received standard feed. The villi of immature broilers (19 days old) administered antibiotics had a larger surface area and their lymphocyte and basophil counts were higher compared to broilers from the probiotic and control groups. The cecal microbiomes of mature broilers (29 days old) that received probiotics had higher levels of Enterobacteriaceae, but lower numbers of Clostridiales, Brucellaceae, Synergistaceae, Erysipelotrichaceae and Coriobacteriaceae compared to the antibiotic-treated group. A decline in the bioluminescence of Listeria monocytogenes observed for broilers on probiotics suggested that the probiotic may be used to control bacterial infections. No significant differences in total red blood cell, haemoglobin and haematocrit content, and mean values for corpuscular volume, corpuscular haemoglobin and corpuscular haemoglobin numbers were recorded amongst broilers from the different treatment groups. This study provides valuable information on the health and performance of broilers when administered probiotics and antibiotics as additives.