Call number: LD2668 .T4 1979 L37 / Master of Science

Corrigenda inserted behind title page. Copies of author's previously published articles inserted. Bibliography: leaves 193-210. This study investigated whether estrogen could modulate the proteins associated with calcium transport (eg calcium binding protein, calbindin D28k) in the intestinal tissue during sexual maturation of laying hens. The first study investigated the temporal and spatial expression of estrogen receptors (ER) and calcium binding protein in jejunal tissue. Findings indicated the potential of estrogen to induce calbindin D28K in the intestinal tissue, from which it can be concluded that estrogen may increase calcium absorption and consequently calcium retention. It was shown that the amount of estrogen normally present in the reproductive system is sufficient for the normal capacity of egg and eggshell production. Egg production and shell quality were significantly reduced by phytoestrogen. It is recommended that the concentration of phytoestrogen in poultry diets be investigated in more detail as it may act as an anti-nutritive factor and affect metabolism and productivity.

Thesis (M. Tech. Agriculture, Tshwane University of Technology, 2011. / To increase local growth linkages of smallholder broiler enterprises in rural areas a single-phase, on-farm processed, mash diet, consisting of boiled and ground full-fat soya beans and ground yellow maize grain fortified with lysine, methionine and selected mineral nutrients was first developed and then tested. Financial analysis showed that net operating expenses of broiler enterprises that used the experimental diet were higher than those of similar enterprises using the control diet, but differences in net operating income were only significant in one of the two runs of the experiment. The main economic benefit of using the experimental diet was the added value to the local economy, which increased from 20 % of the retail value of broiler chickens in the case of enterprises using the control diet to 70 % when using the experimental diet.

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The potential of lignin and mannanoligosaccharides (MOS), as alternatives to antibiotic growth promoters was evaluated in broilers. Dietary treatments included: (1) negative control (CTL-, antibiotic free); (2) positive control (CTL+, 11 mg/kg virginiamycin); (3) MOS (diet 1 + Bio-Mos: 0.2% to 21 d and 0.1% thereafter); (4) LL (diet 1 + 1.25% Alcell lignin); (5) HL (diet 1 + 2.5% Alcell lignin). Bodyweight and feed conversion were not different when broilers were fed the CTL+, MOS, LL or HL diet. Birds fed MOS or LL had increased jejunum villi height (P < 0.05) and greater goblet cell number per villus (P < 0.05) when compared to those fed the CTL+ diet. MOS and LL increased (P < 0.05) the cecal populations of Lactobacilli and Bifidobacteria when compared to CTL+ fed birds. However, Lactobacilli and Bifidobacteria loads were lowest (P < 0.05) in birds fed the CTL+ or HL diet. Litter E. coli load was reduced (P < 0.05) when birds were fed MOS than when fed the CTL+ diet, but comparable to LL or HL fed birds. In birds challenged with pathogenic strains of E. coli (O2 and O88 serotypes) and fed the MOS or HL diet, the cecal population of total E. coli was lower (P < 0.05) than those fed the CTL+ diet; LL fed birds tended to have lower E. coli load than CTL+ fed birds. In summary, birds fed the MOS or LL diet had comparative advantage over CTL+ fed birds as evidenced by increased cecal populations of Lactobacilli and Bifdobacteria, increased villi height and greater goblet cell number in the jejunum, lower E. coli load in the litter, and lower cecal population of E. coli after an in vivo challenge with pathogenic strains of E. coli. Therefore, MOS and lignin could be regarded as natural alternatives to antibiotic growth promoters in poultry production. / Key words. Antibiotics, mannanoligosaccharides, lignin, gut health, broilers.

A study was conducted to examine the response to feeding flaxseed (FS) and probiotics on plasma and egg yolk cholesterol and plasma fatty acid profile in laying hens. A total of 576 Single Comb White Leghorn hens (SCWL) at 26 weeks of age were fed diets containing 15% FS and a corn-soybean meal diet (C) supplemented with and without ferlac 25 (F25) or Lactobacillus acidophilus (LA). Feed consumption was significantly (p < 0.05) increased by FS supplemented with both F25 and LA. Dietary treatments had no significant (p > 0.05) effect on feed conversion. Egg production was significantly (p < 0.05) higher among the FS probiotic supplemented diets and significantly (p < 0.05) lower for dietary FS supplemented with LA. However, egg yolk weight did not respond to dietary treatments (p > 0.05). Body weight was significantly low for all FS fed groups. Shell thickness was not statistically significant (p > 0.05) among experimental treatments, while haugh units were significantly (p < 0.05) higher for FS group supplemented with LA. Probiotic supplementation significantly (p < 0.05) reduced plasma cholesterol (CHL) from 161mg/dL in C diet to 117mg/dL in probiotic supplemented groups. Plasma triglycerides (TG) were significantly (p < 0.05) reduced from 2.8g/dL in FS to 1.9g/dL in probiotic supplemented groups while egg yolk CHL was significantly (p < 0.05) reduced by probiotic supplementation on FS treatments from 14.04mg/g in FS fed group to 10.16mg/g in LA supplemented FS group. Fatty acids profile in the egg yolk responded significantly (p < 0.05) to dietary treatments. FS treatments with and without probiotic supplementation significantly reduced C18:1 o-9 by 12%; while the PUFA families (o-3 and o-6) were significantly (p < 0.05) increased in FS fed group by 93% and 18%, respectively. C20:4, o-6 was significantly reduced from 6.6mg/g in the C group to 3.96mg/g in Fs groups. (Abstract shortened by UMI.)

This study was designed was to determine the effects of additive supplementation of Moringa oleifera leaf meal on growth performance, digestibility, digestive organ size, intestinal integrity, bone ash content and bone breaking strength, as well as meat yield and quality of broiler chickens. A total of 2400 day-old unsexed Cobb-500 broiler chicks were randomly allocated to 5 treatment groups: T1, positive control, 668 g/ton Salinomycin and 500 g/ton Albac; T2, T3 and T4 contained graded levels of MOLM at 1 percent, 3 percent and 5 percent of dry matter (DM) intake, respectively; and T5, a negative control (0 percent additives) in a complete randomized design experiment. Except for week one, FI and FCR was highest (P < 0.05) in T4 birds; while T1 birds had the highest FI in the period of 22 to 27d (P < 0.05). Throughout the production period, birds supplemented with MOLM had the highest BW (P < 0.05) than the birds fed the control diets. Feed intake (FI) and feed conversion ratio (FCR) among treatments was highest (P < 0.05) in T4 birds during the period of 8 to 14 d; and was highest (P < 0.05) for T1 birds in the period of 22 to 27d. Protein efficiency ratio (PER) and energy utilization efficiency (EEU) ratios were statistically significant among treatments (P < 0.05). However, dietary treatments had no effect (P > 0.05) on the weights of the heart, liver, spleen, or the gizzard, although the bursa for T2 birds was the lightest (P < 0.05); while gizzard erosion score was highest in T2 birds. All of the nutrients measured, except for fat, had negative intercepts that were significantly different (P < 0.05) from zero, indicating the presence of endogenous fecal losses. Tibiae length (TL) was highest in T2. The dried defatted weight (DW) was heaviest (P < 0.05) for T3 (11.20 ± 0.347) and T5 (11.08 ± 0.328). A positive correlation (r = 0.667; P < 0.01) between TW and DW was observed. There were no dietary effects on bone breaking strength (BBS), but T1 tibiae had highest resistance to breaking force (T1 > T4 > T3 > T2 > T5). Calcium was highest (P < 0.05) in T1; and lowest inT2 and T5. Phosphorus levels were lowest (P < 0.05) in T1; and highest (P < 0.05) in T5 compared. The highest Ca: P ratio was obtained in T4 (P < 0.05); while the ash percent was highest (P < 0.05) in T1. Drip loss increased as L* values increased; and a negative correlation was observed between L* and pH. On D1, C18: 0 and C22 in T2, while C15:0 was highest in T4. On D1, C20:2, C20:3n6 and C22:6n3 were highest in T2 (P < 0.05); T4 had the highest C18:3n6 (P < 0.05), while C20:2 was highest in T5 (P < 0.05). The P/S ratio on D1 was highest in T4; while n-6/n-3 was highest in T1; and n-3 was highest in T3. On D8, the n-3 was highest in T1 (P < 0.05). Results of the current study show that supplementation of M. oleifera leaf at additive levels of up to 5 percent of the bird’s DMI does have the potential to influence the bird performance without any detrimental effects on nutrient utilization, bird health, bone strength and/or meat quality, which can be concluded that MOLM enhanced the bird’s genetic potential for optimal productivity.

The objectives o-f this research were to investigate the effects of blending Canbra or Canola oil with other oils or fats on the nutritive value and autoxidative stability of the blended oils, and to investigate the possibility of using hydrolyzed oils (free fatty acids) in the study of fatty acid balancing. Canbra oil (containing 6.1% erucic acid) was blended with sunflower oil or animal lard 1/1 (w/w). Canola oil (0.55% erucic acid) was blended with sunflower oil in the ratios 9/1, 8/2, 7/3, 6/4 and 5/5. The nutritional value was assayed using growing chicks fed lipid at 3% in a practical diet during a 4 week feeding period. Evaluation was made using body weight, weight gain, feed consumption, feed conversion, feed digestibility, lipid digestibility, total fatty acid digestibility, metabolizable energy and individual fatty acid digestibility. Results show that Canbra oil is equivalent to animal lard but significantly inferior to sunflower oil. Blending Canbra oil and sunflower oil or animal lard improved chick growth and fatty acid utilization over that demonstrated by the Canbra oil alone. Canola oil was equivalent to sunflower oil and soybean oil in supporting chick growth. The 7/3 and 5/5 blends showed synergistic improvement in promoting growth, fatty acid, protein and metabolizable energy utilization. It was concluded that Canola oil is nutritionally equivalent to either sunflower oil or soybean oil and that blending with sun-flower oil further improved its nutritional value. Oil blending rendered no significant detrimental effects on stability. The fatty acids of hydrolyzed Canola and sunflower oil showed nutritive performance equivalent to that of the intact oils. The fatty acids of a hydrolyzed 5/5 blend of Canola oil and sunflower oil showed reduced absorption of some fatty acids and the fatty acids of hydrolyzed soybean oil showed reduced diet and fatty acid absorption relative to the intact oils. These results demonstrate that feeding hydrolyzed oils may be a useful method of investigating fatty acid balance but more research is required in this area. / Land and Food Systems, Faculty of / Graduate

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