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 varying concentrations of dietary crude protein and metabolizable energy on laying performance of Pearl Grey guinea fowl hens.

This study was conducted to evaluate optimum dietary concentrations of ME and CP for egg production performance of the Pearl Gray guinea fowl laying hens. In a 2 x 3 factorial arrangement, 360 Pearl Gray guinea fowl replacement pullets (22 wk of age) were randomly assigned to experimental diets with 2,800 and 2,900 kcal of ME/kg of diet, each containing 14, 16, and 18% CP, respectively. Each dietary treatment was replicated 4 times, and feed and water were provided ad libitum. Experimental birds were raised in laying cages and received 16 h of light throughout the study period. The birds were observed for feed consumption, hen-day egg production (HDEP), egg weight (EW), egg mass (EM), feed conversion ratio, internal egg quality, shell thickness (ST), and BW at the end of each 28-d lay period at 26 to 50 wk of age and at 62 to 86 wk of age. Mortality was recorded as it occurred. Mean HDEP, EW, EM, and ST were higher (P < 0.05) in hens receiving diets with 2,800 kcal of ME/kg of feed than those fed diets containing 2,900 kcal of ME/kg of diet. Hens on 14% CP diets also exhibited higher (P < 0.05) HDEP, EM, and ST than those fed diets containing 16 and 18% CP diets. Mean feed conversion ratio of birds on 2,800 kcal of ME/kg of diet and 14% CP diets were significantly lower than those of hens on other dietary treatments. Differences in feed consumption, EW, internal egg quality, BW, and mortality among dietary ME and CP concentrations were not significant (P > 0.05). Overall, diets composed of 2,800 kcal of ME/kg of diet and 14% CP were utilized more efficiently by the Pearl Gray guinea fowl laying hens at 26 to 50 and 62 to 86 wk of age.

Effect of varying metabolizable energy and crude protein concentrations in diets of Pearl Gray guinea fowl pullets. 2. Egg production performance.

The effect of ME and CP concentrations during the growth phase of Pearl Gray guinea fowl pullets on their egg production performance was evaluated. In a 3 x 3 factorial arrangement, five hundred forty 1-d-old Pearl Gray guinea keets were randomly assigned to experimental diets with 2,900, 3,000, and 3,100 kcal of ME/kg of diet; each contained 20, 22, and 24% CP, respectively, from 0 to 8 wk of age (WOA). From 9 to 16 WOA, experimental diets had 3,000, 3,100, and 3,200 kcal of ME/kg of diet, and each contained 17, 19, and 21% CP, respectively. At 17 to 22, 23 to 27, and 28 to 56 WOA, experimental diets were composed of 3,000, 2,900, and 2,800 kcal of ME/kg, and each had 18, 17, and 16% CP, respectively. Dietary treatments were replicated 4 times, and feed and water were provided ad libitum. Body weights were measured weekly from 0 to 22 WOA, and at 28 to 56 WOA the birds were observed for feed consumption, age at first egg, hen-day egg production (HDEP), egg weight, egg mass (EM), feed conversion ratio (FCR), internal egg quality (IEQ), shell thickness (ST), and BW at the end of each 28-d lay period for 7 consecutive periods. Mortality was recorded as it occurred. Overall, BW gains were higher (P < 0.05) in birds fed 3,000 and 3,100 Kcal of ME/kg and 24% CP from 0 to 8 WOA than other dietary treatments. Percentages HDEP, EM, and IEQ were higher (P < 0.05) and FCR was lower (P < 0.05) in pullets fed 3,000 and 3,100 kcal of ME/kg diet at 0 to 8 WOA than those fed 2,900 kcal of ME/kg. Birds on 22 and 24% CP diets at 0 to 8 WOA also exhibited higher HDEP, EM, and lower FCR than those on 20% CP diets. Thus, feeding 3,000 to 3,100 kcal of ME/kg of diet and 22 to 24% CP at 0 to 8 WOA and 3,100 to 3,200 kcal of ME/kg of diet and 19 to 21% CP at 9 to 16 WOA improved HDEP, EM, IEQ, and FCR of Pearl Gray guinea fowl laying pullets at 28 to 56 WOA.

Effect of varying metabolizable energy and crude protein concentrations in diets of Pearl Gray guinea fowl pullets 1. Growth performance.

This study was undertaken to assess dietary ME and CP concentrations for optimum growth performance of Pearl Gray guinea fowl pullets. In a 3 x 3 factorial arrangement, 540 one-day-old Pearl Gray guinea keets were randomly assigned to experimental diets with 2,900, 3,000, and 3,100 kcal of ME/kg of diet, each containing 20, 22, and 24% CP, respectively, from 0 to 8 wk of age (WOA). From 9 to 16 WOA, these diets were adjusted to contain 3,000, 3,100, and 3,200 kcal of ME/ kg, and each had 17, 19, and 21% CP, respectively. Each dietary treatment was replicated 4 times, and feed and water were provided ad libitum. Body weight and feed consumption were measured weekly. Mortality was recorded as it occurred. Overall, feed consumption was higher in birds on 2,900 and 3,000 kcal of ME/kg of feed and the 24 and 21% CP diets than other dietary treatments at 0 to 8 and 9 to 16 WOA, respectively. When compared with other dietary treatments, cumulative BW gains were higher (P < 0.05) in birds fed 3,000, 3,000 and 3,100, and 3,100 and 3,200 kcal of ME/kg of diet at 2 to 5, 6 to 8, and 9 to 16 WOA, respectively. Pullets receiving 24 and 21% CP diets also exhibited higher BW gains than other dietary treatments at 0 to 8 and 9 to 16 WOA, respectively. Feed conversion ratios were lower (P < 0.05) in birds fed 3,000, 3,100, and both 3,100 and 3,200 kcal of ME/kg of diet at 1 to 5, 6 to 8, and 9 to 16 WOA, respectively, than other dietary treatments. Pullets fed 24% CP diets and either 17 or 19% CP diets exhibited lower (P < 0.05) feed conversion ratios than other dietary treatments at 1 to 8 and 9 to 16 WOA, respectively. Thus, diets comprising 3,000 and 3,100 kcal of ME/kg were utilized more efficiently by the Pearl Gray guinea fowl pullets at 0 to 5 and 5 to 16 WOA, respectively. Also, these birds more efficiently utilized diets containing 24 and 17% CP at 0 to 8 and 9 to 16 WOA, respectively.

Laying performance of pearl gray guinea fowl hens as affected by caging density.

The caging density required for optimal egg production by various avian species and varieties is highly variable. Even so, little is known of the required cage density for optimum performance of the laying guinea fowl (Numida meleagris). The objective of this study was to assess the effect of varying cage densities on production performance of pearl gray guinea fowl laying hens. In 3 replicates, 270 pearl gray guinea hens [28 wk of age (WOA)] were weighed individually and randomly assigned to laying cages at densities of 1, 2, and 3 birds/cage, equivalent to 1394, 697, and 465 cm2/bird, respectively. During the experiment, all birds received a 16-h lighting regimen and were fed the same diet, comprising 2800 kcal of ME/kg of diet and 16% CP (28 to 59 WOA) and 2800 kcal of ME/kg of diet and 14% CP (60 to 76 WOA). Feed and water were provided for ad libitum consumption. Experimental birds were observed for feed consumption (FC), hen-day egg production (HDEP), egg weight, egg mass (EM), feed conversion ratio, internal egg quality, and shell thickness at the end of each 28-d lay period for 11 consecutive periods. Mean FC and HDEP decreased significantly with increases in cage density, such that 1394 > 697 > 465 cm2/bird. Mean EM was also higher (P < 0.05) for birds reared in cages at 1394 cm2/bird than those reared in cages at 697 and 465 cm2/bird (24.8, 17.4, and 14 g/hen per d, respectively). Feed conversion, HDEP, and EM were negatively correlated with cage density (P < 0.05). Mean feed conversion ratio and percentage of mortality were also lower in birds reared in cages at 1394 cm2/bird than in other treatment groups. Therefore, laying guinea fowl hens exhibited superior performance when raised at a density of 1 bird/cage (1394 cm2/bird) than those reared at densities of 2 and 3 birds/cage (697 and 465 cm2/bird, respectively).

Modeling growth characteristics of meat-type guinea fowl.

This study was conducted to describe the growth pattern of the French guinea fowl, a meat-type variety. Using BW data from hatch to 9 wk, 2 nonlinear mathematical functions (Gompertz and logistic) were used to estimate growth patterns of the French guinea fowl. The French guinea fowl did not exhibit sexual dimorphism for growth characteristics. From the Gompertz model, the asymptotic BW, growth rate, and age at maximum growth were 2.05 kg, 0.25 kg/wk, and 5.74 wk in males, respectively, and 2.03 kg, 0.25 kg/wk, and 5.72 wk in females, respectively. The ages at maximum growth were 5.75 and 5.74 wk for males and females, respectively, using the logistic model. Differences in asymptotic BW between males and females were not significant in both Gompertz and logistic models. However, the average asymptotic BW of about 1.50 kg for both sexes predicted by the logistic model was below the average predicted BW from the Gompertz model (2.04 kg) at 9 wk. Also, the logistic model overestimated hatching weight (0.06 kg) more than the Gompertz model (0.03 kg), suggesting that the growth pattern of the French guinea fowl is Gompertz. The inverse relationship between the asymptotic weight and age at maximum growth of the French guinea fowl is similar to that of the pearl gray guinea fowl, chickens, quail, and ducks. Understanding the growth characteristics of French guinea fowl will contribute to the efforts of improving production efficiency of this least studied avian species.

Growth characteristics of pearl gray guinea fowl as predicted by the Richards, Gompertz, and logistic models.

This study was undertaken to describe the growth pattern of the pearl gray Guinea fowl. Using BW data from hatch to 22 wk, 3 nonlinear mathematical functions (Richards, Gompertz, and logistic) were used to estimate growth patterns of the pearl gray guinea fowl. The logistic and Gompertz models are a special case of the Richards model, which has a variable point of inflection defined by the shape or growth trajectory parameter, m. The shape parameter m was 1.08 and 0.98 in males and females, respectively, suggesting that the growth pattern of the pearl gray female guinea fowl is Gompertz. The pearl gray guinea fowl exhibited sexual dimorphism for their growth characteristics. From the Gompertz model, the asymptotic BW, growth rate, and age at maximum growth were 1.62 kg, 0.22 kg/wk, and 6.65 wk in males, respectively, and 1.70 kg, 0.19 kg/wk, and 6.70 wk in females, respectively. The ages at maximum growth were 6.65, 6.47, and 8.12 wk for the Richards, Gompertz, and logistic models, respectively. The pearl gray guinea fowl females have a higher asymptotic BW compared with the males. The average asymptotic BW of about 1.57 kg for both sexes predicted by the logistic model was below the average predicted BW from the Richards (1.66 kg) and Gompertz (1.67 kg) models, respectively, at 22 wk of age. The inverse relationship between the asymptotic weight and both relative growth and age at maximum growth of the pearl gray guinea fowl is similar to that of chickens, quail, and ducks. Success in studying the growth characteristics of guinea fowl will contribute to the efforts of genetically improving this least-studied avian species.

Effects of dietary metabolizable energy and crude protein concentrations on growth performance and carcass characteristics of French guinea broilers.

This study was undertaken to assess dietary CP and ME concentrations for optimum growth performance and carcass characteristics of French guinea broilers. In a 3 x 3 factorial arrangement, 396 1-d-old French guinea keets were randomly assigned to experimental diets with 3,050, 3,100, and 3,150 kcal of ME/kg of diet; each contained 21, 23, and 25% CP, respectively, from 0 to 4 wk of age (WOA). From 5 to 8 WOA, experimental diets had 3,100, 3,150, and 3,200 kcal of ME/kg of diet, and each contained 19, 21, and 23% CP, respectively. Each dietary treatment was replicated 3 times, and feed and water were provided ad libitum. Body weight and feed consumption were measured weekly, whereas carcass characteristics were evaluated at 8 WOA. For the most part, birds on 3,100 and 3,150 kcal of ME/kg of diet at 0 to 4 WOA exhibited greater (P < 0.05) BW gain, greater carcass and breast weights (P < 0.05), and lower (P < 0.05) feed consumption and feed conversion ratios (FCR) than those on a diet with 3,050 kcal of ME/kg. Mean feed consumption of birds fed 25% CP diets was higher (P < 0.05) than those on other dietary CP concentrations. Mean BW gain, FCR, and carcass and breast weights of birds fed 25 and 23% CP diets from 0 to 4 WOA were not different (P > 0.05), but they were better (P < 0.05) than those of birds on 21% CP diets. Positive correlations (P < 0.01) were noted between live weight and weight of carcass, breast, thigh, drumstick, and wing of guinea broilers. Thus, diets with 3,100 kcal of ME/kg and 23% CP or with 3,150 kcal of ME/kg and 21% CP at 0 to 4 WOA and 5 to 8 WOA, respectively, were used more efficiently by French guinea broilers.