Nathaniel Adefope

An initial map of chromosomal segmental copy number variations in the chicken

BackgroundChromosomal segmental copy number variation (CNV) has been recently recognized as a very important source of genetic variability. Some CNV loci involve genes or conserved regulatory elements. Compelling evidence indicates that CNVs impact genome functions. The chicken is a very important farm animal species which has also served as a model for biological and biomedical research for hundreds of years. A map of CNVs in chickens could facilitate the identification of chromosomal regions that segregate for important agricultural and disease phenotypes.ResultsNinety six CNVs were identified in three lines of chickens (Cornish Rock broiler, Leghorn and Rhode Island Red) using whole genome tiling array. These CNVs encompass 16 Mb (1.3%) of the chicken genome. Twenty six CNVs were found in two or more animals. Whereas most small sized CNVs reside in none coding sequences, larger CNV regions involve genes (for example prolactin receptor, aldose reductase and zinc finger proteins). These results suggest that chicken CNVs potentially affect agricultural or disease related traits.ConclusionAn initial map of CNVs for the chicken has been described. Although chicken genome is approximately one third the size of a typical mammalian genome, the pattern of chicken CNVs is similar to that of mammals. The number of CNVs detected per individual was also similar to that found in dogs, mice, rats and macaques. A map of chicken CNVs provides new information on genetic variations for the understanding of important agricultural traits and disease.

Prevalence and Antimicrobial Resistance of Pathogenic Bacteria in Chicken and Guinea Fowl

This study was conducted to compare the presence and antimicrobial susceptibility of Campylobacter, Salmonella spp., and other enteric bacteria between chickens and guinea fowls. Birds were reared on enclosed concrete floor housing covered with pine wood shavings litter material. Chicken (n = 40) and guinea fowl (n = 40) carcasses, drinking water (10 mL; n = 40), and litter (10 g; n = 40) were aseptically collected randomly from a poultry farm and analyzed within 1 h of collection. Individual pens served as experimental units and were replicated twice. Campylobacter spp., Salmonella spp., and other enterobactericeae were isolated and identified using standard selective media and biochemical tests. Isolates were tested for sensitivity to tetracycline, ampicillin, streptomycin, kanamycin, nalidixic acid, gentamicin, erythromycin, ciprofloxacin, cefoxitin, and colistin using the Kirby-Bauer disk diffusion test. Campylobacter spp. and Salmonella spp. were isolated from 28 and 35% of whole carcass rinses of chickens and from 18 and 23% of whole carcass rinses of guinea fowl, respectively. Although only Salmonella spp. were recovered from drinking water, both Salmonella and Campylobacter spp. were recovered from litter material. Campylobacter upsaliensis was recovered only in the guinea fowl, whereas Klebsiella oxytoca and Enterobacter sakazakii were recovered only in chickens. Although no antibiotic resistance was determined in Campylobacter upsaliensis, most Campylobacter, Salmonella, and Escherichia coli isolates from both chickens and guinea fowl were resistant to antibiotics such as ampicillin, kanamycin, erythromycin, and nalidixic acid.

Gompertz-Laird model prediction of optimum utilization of crude protein and metabolizable energy by French guinea fowl broilers.

This study was conducted to assess the influence of dietary CP and ME on growth parameters of the French guinea fowl, a meat-type variety. In a 2 x 3 x 3 factorial arrangement, 297 one-day-old French guinea keets (162 females and 135 males) were randomly assigned to experimental diets comprising 3,050, 3,100, and 3,150 kcal of ME/kg, each containing 21, 23, and 25% CP from hatch to 4 wk of age (WOA), and 3,100, 3150, and 3,200 kcal of ME/kg, each containing 19, 21, and 23% CP at 5 to 8 WOA. Using BW and G:F data from hatch to 8 WOA, the Gompertz-Laird growth model was employed to estimate growth patterns of the French guinea fowl. Mean differences in exponential growth rate, age of maximum growth, and asymptotic BW among dietary CP and ME levels were not significant. However, instantaneous growth rate and weight at inflection point were significantly higher (P < 0.05) in birds on the 25% CP diet than those on the 21% CP diet at hatch to 4 WOA (1.12 kg/wk and 0.79 kg vs. 1.04 kg/wk and 0.74 kg, respectively). The exponential growth rate was also higher (P < 0.05) in birds fed the 3,050 kcal of ME/kg diet with either 23 or 25% CP than those fed diets containing 3,050 kcal of ME/kg and 21% CP. Mean G:F was higher (P < 0.05) in birds fed diets containing 3,050 kcal of ME/kg and either 21 or 23% CP than those in other dietary treatments. Therefore, based on the Gompertz-Laird growth model estimates, feeding 21 and 23% CP and 3,100 kcal of ME/kg at hatch to 4 WOA and 19 and 21% CP with 3,150 kcal of ME/kg at 5 to 8 WOA can be recommended as adequate for growth for the French guinea fowl broilers.

The effect of floor density on growth performance and carcass characteristics of French guinea broilers

The floor density required for optimal growth performance of different avian species and varieties is highly variable. Little is known of the required floor density for optimum performance of the French guinea fowl (Numida meleagris) broiler. The objective of this study was to assess the effect of varying floor densities on growth performance and carcass characteristics of the French guinea broiler. In 3 replicates, 687 one-day-old French guinea keets were weighed individually and randomly assigned to floor pens covered with pine wood shavings at 69, 60, 53, and 47 birds/pen, equivalent to densities of 15.6, 13.6, 12, and 10.7 birds/m(2), respectively. Birds in these floor densities were allowed feeder space of 2.7, 3.1, 3.5, and 4 cm/bird, respectively, and water space of 1.4, 1.6, 1.8, and 2.0 cm/bird, respectively. All birds received a 23-h lighting regimen and were fed the same diet comprising 3,100 kcal of ME/kg of diet and 23% CP from 1 d old to 4 wk of age (WOA) and 3,150 kcal of ME/kg of diet and 21% CP at 5 to 8 WOA. Feed and water were provided for ad libitum consumption. Body weight and feed consumption were measured weekly, whereas carcass characteristics were evaluated at 8 WOA. Overall, feed consumption was significantly higher (P < 0.05) in birds raised in 10.7 birds/m(2) than other treatment groups. Birds in floor densities of 12 and 15.6 birds/m(2) also consumed 6% more feed than those raised at 13.6 birds/m(2). Mean BW gain of birds in floor density of 15.6 birds/m(2) was significantly lower (P < 0.05) than that of birds in other floor densities. In general, significantly lower feed conversion ratios and higher carcass yields were observed in birds raised in floor densities of 13.6 and 12 birds/m(2) than those raised in floor densities of 15.6 and 10.7 birds/m(2). Therefore, French guinea broilers exhibited superior performance when raised at floor densities of 13.6 and 12 birds/m(2) than those reared at floor densities of 15.6 and 10.7 birds/m(2).

Effect of floor density on growth performance of Pearl Grey guinea fowl replacement pullets

Little is known of the optimal floor density for the Pearl Grey (PG) guinea fowl pullet. Hence, the objective of this study was to determine the effect of varying floor density on the growth performance of PG guinea fowl pullets. In 3 replicates, 1-d-old guinea keets (n = 786) were weighed individually and randomly assigned to floor pens covered with pine wood shavings at 80, 69, 60, and 53 birds/pen, equivalent to densities of 18, 15.6, 13.6, and 12 birds/m(2), respectively. The birds were allowed feeder space of 2.3, 2.7, 3.1, and 3.5 cm/bird, respectively, and water space of 1.2, 1.4, 1.6, and 1.8 cm/bird, respectively. The photoperiod was 23 h at 0 to 11 wk of age (WOA) and 8 h at 12 to 16 WOA. Birds were fed diets comprising 3,000 and 3,100 kcal of ME/kg of diet at 0 to 4 and 5 to 8 WOA, respectively, and 24% CP. At 9 to 16 WOA, the diets comprised 3,100 kcal of ME/kg and 18% CP. Feed and water were provided for ad libitum consumption. Body weight and feed consumption were measured weekly. Overall, BW gains were higher (P < 0.05) and feed conversion ratios (FCR) were significantly lower in birds reared at a floor density of 18 birds/m(2) than in birds reared on other treatments at 0 to 8 WOA. However, at 9 to 16 WOA, birds at floor densities of 12 birds/m(2)exhibited higher BW gain and feed consumption and lower FCR (P < 0.05) than those at floor densities of 13.6, 15.6, and 18 birds/m(2). Therefore, this study suggests an optimum floor density of 18 and 12 birds/m(2) at 0 to 8 and 9 to 16 WOA, respectively, to achieve the highest possible FCR for the PG guinea fowl replacement pullets.