Research Articles (Animal Sciences)

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Browsing Research Articles (Animal Sciences) by Subject "Amino acids"

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    Amino acid requirements of South African Mutton Merino lambs 3. Duodenal and whole empty body essential amino acid profile
    (South African Society for Animal Science, 1999) Ferreira, A. V.; Van der Merwe, H. J.; Loest, C. A.
    The duodenal and whole empty body essential amino acid (EAA) profile of South African Mutton Merino lambs fed a standard growth diet was investigated. The data of 20 lambs were used. With the exception of phenylalanine, significant (p < 0.05) differences between the EAA concentrations of the duodenal digesta and whole empty body occurred. From the chemical score, it was concluded that the duodenal digesta was first-limiting in histidine and second-limiting in methionine, followed by threonine and arginine for the whole empty body growth of South African Mutton Merino ram lambs fed a standard diet high in rumen degradable protein. A calculated essential amino acid composition for the correction of imbalances in duodenal digesta was as follows (%): 11.21 arginine; 14.53 histidine; 8.17 isoleucine; 9.97 leucine; 8.64 lysine; 13.87 methionine; 9.97 phenylalanine; 12.54 threonine and 11.11 valine.
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    The effect of different combinations of dietary energy and protein on the composition of ostrich eggs
    (South African Society for Animal Science, 2003) Brand, Z.; Brand, T. S.; Brown, C. R.
    Nutrition of breeding female birds can influence egg quality and is therefore extremely important for the development of the embryo and the successful hatching of a high quality chick. We investigated the effect of combining different levels of dietary energy and protein, with accompanied amino acid levels, in the diets of female ostriches on the composition of their eggs. Ninety pairs of breeding ostriches were divided randomly into nine groups of 10 pairs per group in a factorial design with three energy and three protein levels. The groups were fed diets with levels of 7.5, 8.5 and 9.5 MJ metabolisable energy/kg, each combined with each one of three protein levels 105, 120 and 135 g/kg respectively. Fresh eggs were collected from each group at the end of the breeding season and the albumen and yolk separated and analysed for protein and lipid content and for amino acid and mineral composition. No significant interaction between energy and protein levels occurred. Despite some differences in egg composition and amino acid concentrations, different dietary energy and protein levels for the most part had little or no effect on the composition of ostrich eggs.
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    Effect of varying levels of protein concentration on production traits of ostriches (Struthio camelus var. domesticus)
    (South African Society for Animal Science, 2019-07-28) Brand, T. S.; Viviers, S. F.; Van Der Merwe, J.; Hoffman, L. C.
    The ostrich industry is poised to recover from the recent lifting of the four-year export ban on fresh meat products to the European Union EU). However, during this period profit margins were severely affected and the need to minimize input costs was as important as it ever was, particularly nutrition. The aim of this study was to evaluate the influence of varying protein concentrations in the diets of slaughter ostriches on the production traits. Five treatment diets were formulated for each feeding phase (pre-starter, starter, grower and finisher), with a control diet, two diets that decreased in protein content and two diets that increased in protein concentration. There were three replications per treatment, resulting in 15 camps, which contained 20 chicks each. Differences were found in live weight of the birds at the end of each feeding phase, except for the finisher phase. Differences were found among the diets for dry matter intake (DMI), average daily gain (ADG), and feed conversion ratio (FCR). The control diet and the two diets that were formulated with higher protein concentrations had higher DMI values, better ADG, and more efficient FCR. Differences were found in cold carcass weights and thigh weights for the birds that were exposed to the treatment diets. The results indicated that the birds on the control diet and on the diets containing higher concentrations of protein, although not differing from each other, consistently outperformed the diets with lower concentrations of protein. From a financial standpoint it can be concluded that it does not make sense to increase the protein concentration in the diets beyond that currently used in the ostrich industry, while a decrease in protein concentration resulted in decreased production performance.