Analysis of growth curves of indigenous male Venda and Naked Neck chickens

The objective of this work was to estimate and compare the growth curve parameters for live weight of indigenous Venda and Naked Neck chickens and carry out some analyses to test the existence of differences in the growth pattern between these breeds. The data were collected from the two breeds of chickens that were reared from day-old to 21 weeks of age. Two hundred chickens (100 of each breed) were used. Three different non-linear models, namely Gompertz, Logistic and Richards, were used to define the growth curves of the chickens. Models were compared using Coefficients of determination (R2 values), A parameter values, the Durbin-Watson Statistic (DW) test for autocorrelation, computing difficulty based on the number of iterations needed for convergence and size of residual variances. The R2 were high for all models: 0.996, 0.990 and 0.997 for Gompertz, Logistic and Richards, respectively. Residual variances were 2240, 5924 and 1154 for Gompertz, Logistic and Richards, respectively. The Gompertz model was observed to be suitable for explaining the growth of the chickens. Breed differences were observed in the growth parameters of chickens. The Venda breed was observed to be late maturing and heavier at maturity while the Naked Neck was shown to have a higher growth rate, reaching maturity earlier but attaining a lighter mature weight. Keywords: Growth parameters, growth models, breed differences South African Journal of Animal Science Vol. 37 (1) 2007: pp. 21-2

Excellent Adherence to Antiretrovirals in HIV plus Zambian Children Is Compromised by Disrupted Routine, HIV Nondisclosure, and Paradoxical Income Effects

Introduction A better understanding of pediatric antiretroviral therapy (ART) adherence in sub-Saharan Africa is necessary to develop interventions to sustain high levels of adherence. Methodology/Principal Findings Adherence among 96 HIV-infected Zambian children (median age 6, interquartile range [IQR] 2,9) initiating fixed-dose combination ART was measured prospectively (median 23 months; IQR 20,26) with caregiver report, clinic and unannounced home-based pill counts, and medication event monitoring systems (MEMS). HIV-1 RNA was determined at 48 weeks. Child and caregiver characteristics, socio-demographic status, and treatment-related factors were assessed as predictors of adherence. Median adherence was 97.4% (IQR 96.1,98.4%) by visual analog scale, 94.8% (IQR 86,100%) by caregiver-reported last missed dose, 96.9% (IQR 94.5,98.2%) by clinic pill count, 93.4% (IQR 90.2,96.7%) by unannounced home-based pill count, and 94.8% (IQR 87.8,97.7%) by MEMS. At 48 weeks, 72.6% of children had HIV-1 RNA <50 copies/ml. Agreement among adherence measures was poor; only MEMS was significantly associated with viral suppression (p = 0.013). Predictors of poor adherence included changing residence, school attendance, lack of HIV disclosure to children aged nine to 15 years, and increasing household income. Conclusions/Significance Adherence among children taking fixed-dose combination ART in sub-Saharan Africa is high and sustained over two years. However, certain groups are at risk for treatment failure, including children with disrupted routines, no knowledge of their HIV diagnosis among older children, and relatively high household income, possibly reflecting greater social support in the setting of greater poverty

Excellent Adherence to Antiretrovirals in HIV+ Zambian Children Is Compromised by Disrupted Routine, HIV Nondisclosure, and Paradoxical Income Effects

INTRODUCTION: A better understanding of pediatric antiretroviral therapy (ART) adherence in sub-Saharan Africa is necessary to develop interventions to sustain high levels of adherence. METHODOLOGY/PRINCIPAL FINDINGS: Adherence among 96 HIV-infected Zambian children (median age 6, interquartile range [IQR] 2,9) initiating fixed-dose combination ART was measured prospectively (median 23 months; IQR 20,26) with caregiver report, clinic and unannounced home-based pill counts, and medication event monitoring systems (MEMS). HIV-1 RNA was determined at 48 weeks. Child and caregiver characteristics, socio-demographic status, and treatment-related factors were assessed as predictors of adherence. Median adherence was 97.4% (IQR 96.1,98.4%) by visual analog scale, 94.8% (IQR 86,100%) by caregiver-reported last missed dose, 96.9% (IQR 94.5,98.2%) by clinic pill count, 93.4% (IQR 90.2,96.7%) by unannounced home-based pill count, and 94.8% (IQR 87.8,97.7%) by MEMS. At 48 weeks, 72.6% of children had HIV-1 RNA <50 copies/ml. Agreement among adherence measures was poor; only MEMS was significantly associated with viral suppression (p = 0.013). Predictors of poor adherence included changing residence, school attendance, lack of HIV disclosure to children aged nine to 15 years, and increasing household income. CONCLUSIONS/SIGNIFICANCE: Adherence among children taking fixed-dose combination ART in sub-Saharan Africa is high and sustained over two years. However, certain groups are at risk for treatment failure, including children with disrupted routines, no knowledge of their HIV diagnosis among older children, and relatively high household income, possibly reflecting greater social support in the setting of greater poverty

Breed and Sex Differences in the Gross Anatomy, Digesta pH and Histomorphology of the Gastrointestinal Tract of Gallus Gallus Domesticus

ABSTRACT A study was conducted to investigate the influence of breed and sex in the gross anatomy, digesta and histology of Ross 308 broiler and Venda chickens. Chickens were slaughtered at 90 days of age and the pH of the digestive organs was measured immediately after slaughter. The digestive organ weights and lengths of Ross 308 broiler and Venda chickens were measured. Tissue samples of the duodenum, ileum and jejunal from each treatment group were collected and histologically examined. Higher (p<0.05) gizzard pH values were observed in male and female of Ross 308 broiler and Venda chickens. The jejunal and ileal pH values were lower (p<0.05) for Venda chickens than in Ross 308 broiler chickens. The absolute weights of the gastrointestinal tract, crop, proventriculus and gizzard were lighter (p<0.05) in Venda chickens than in Ross 308 broiler chickens. The relative organ weights of the GIT, proventriculus, gizzard and caeca were higher (p<0.05) in Venda chickens than in Ross 308 broiler chickens aged 90 days. Male chickens had higher (p<0.05) relative organ weights than female chickens. Interactions between breed and sex influenced (p<0.05) the absolute weights of the crop, proventriculus, caeca and large intestine. Ileum villus heights of female Venda chickens were higher (p<0.05) than those of female and male Ross 308 broiler and Venda chickens. The male and female Ross 308 broiler chickens had higher (p<0.05) ileum and duodenum crypt depths than male and female Venda chickens. The duodenum and ileum villus height/crypt depth ratios were higher (p<0.05) in male and female Venda chickens than Ross 308 broiler chickens. In overall, male broiler chicken performed better

Agreement between measures (as shown by the difference between methods versus mean adherence value for each child).

<p>The Bland-Altman plots in this figure show pair wise agreement between adherence methods. Each plot indicates the difference between two methods on the vertical axis against the mean of the same methods on the horizontal axis. Data points above the zero line occur when the first method shows higher adherence than the second. On the horizontal axis, data points to the right indicate high adherence from both methods, in which case the maximum possible difference between them is shown by the angled lines.</p