Thesis (M.Sc. (Animal Production)) -- University of Limpopo, 2023 / The development curve of Venda chicken fed with various amounts of citric acid was
evaluated using nonlinear models in an experiment. to ascertain the effects of citric
acid supplementation level on feed intake, body weight increase, and linear
measurements on Venda chickens. 200 male Venda chickens were used in the
experiment which lasted 90 days. The chicks were randomly assigned to four
treatments (0, 12.5, 25 and 50g of citric acid inclusion) with 5 replications, resulting
in 20 floor pens with 10 chicks per replicate. A completely randomized design was
employed as experimental design. Analysis of Variance (ANOVA) was used to
determine the effect of citric acid on feed intake, body weight gain, FCR, GR and
body linear measurements. Three different non-linear models, namely Gompertz,
Weibull, and Richards, were used to define the growth curves of the Venda chickens.
The Duncan multiple range test at the 5% level of significance was utilized to detect
significant differences between the means. Models were compared using coefficients
of determination (R2) and standard errors (SE). The results indicated that feed
intake, body weight, average daily gain and growth rate of Venda chickens were not
affected (p > 0.05) by citric acid supplementation levels. Similarly, Citric acid
supplementation had no effects (p > 0.05) on the shank length and wing length of
Venda chickens. However, feed conversion ratio (FCR) of Venda chickens was
improved (p < 0.05) by with an increase in citric acid supplementation. The Venda
chicken fed citric acid at grower phase and finisher phase had better growth
performances than the starter phase. Citric acid supplementation improved the back
length and thigh length of Venda chickens. The Venda chickens fed citric acid at 25g
inclusion level significantly higher back and thigh length. The coefficient of determination ranged from 0.00 to 0.98 in all the treatments. The Gompertz Model and Richards Models both exhibited the same coefficient of determination across all treatments. The model with the lowest standard error was found to best describe the growth curve of male Venda across all treatments. The Gompertz model was observed to be suitable for explaining the growth of Venda chickens fed with feed without citric acid (CA0g) and citric acid 125g inclusion (CA12.5g). The Richards model was observed to be suitable for explaining the growth of Venda chickens fed citric acid 25g inclusion (CA25g) and citric acid 50g inclusion (CA50g). It is recommended to use a supplement containing lower citric acid to enhance the body linear measurements and growth performance of the chickens. Gompertz and Richards models can be utilized to characterize the growth curve of Venda chickens. / National Research Foundation (NRF)
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:ul/oai:ulspace.ul.ac.za:10386/4305 |
| Date | January 2023 |
| Creators | Zulu, Blantina Fangele |
| Contributors | Gunya, B, Tyasi, T.L. |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | xi, 76 leaves |
| Relation |
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