Comparative study of growth curves in poultry

International audienc

Divergent selection for shape of growth curve in Japanese quail. 4. Carcase composition and thyroid hormones

1. Changes in the relative weights of carcase, abdominal fat, breast and leg muscles, and plasma thyroid hormone concentrations occurring during the first 6 weeks of postnatal growth were analysed in males of HG and LG lines divergently selected for high and low relative body weight (BW) gain between 11 and 28 d of age, respectively, and constant adult BW. 2. The second week of postnatal life was a critical age at which the HG males exhibited a relatively faster growth in comparison to their LG counterparts and permanently exceeded LG males in the percentage by weight of carcase, breast and leg muscle. A higher production of muscle tissues was associated with lower accumulation of abdominal fat before sexual maturity. 3. In general, the plasma T(3) level of HG quail exceeded that of LG quail. Nevertheless, significant differences were found only at 14, 21 and 28 d of age, that is, in the period during which the highest inter-line differences in relative growth rate were noted. Also the T(3)/T(4) ratio followed a similar trend while plasma T(4) level showed no clear and consistent inter-line differences. 4. The results suggest that the selection for the shape of the growth curve, like the selection for body fat, modifies the carcase quality owing to shortening/prolongation of the acceleration growth phase. Individuals with a short acceleration phase of the growth curve are characterised by low carcase quality during the fattening period.status: publishe

Effects of experimentally increased in ovo lysozyme on egg hatchability, chicks complement activity and phenotype in a precocial bird

In birds, spectrum of egg white proteins deposited into the egg during its formation are thought to be essential maternal effects. Particularly, egg white lysozyme (LSM), exhibiting great between and within species variability, is considered to be essential for developing avian embryos due to its physiological, antimicrobial, and innate immune defense functions. However, there have been few studies investigating effects of LSM on early post-hatching phenotype, despite its broad physiological and protective role during embryogenesis. Here, we test how experimentally increased concentrations of egg white LSM affect hatchability in Japanese quail (Coturnix japonica) and chick phenotype immediately after hatching (particularly body weight, tarsus length, plasma LSM concentration, and plasma complement activity). Chicks from eggs with increased LSM concentration displayed reduced tarsus length compared to chicks from control eggs while hatchability, body weight and plasma LSM concentration were unaffected. It is worth noting that no effect of increased in ovo lysozyme on eggs hatchability could be related to pathogen-free environment during artificial incubation of experimental eggs causing minimal pressure on embryo viability. While tangible in vivo mechanisms during avian embryogenesis remain to be tested, our study is the first to document experimentally that egg white LSM appears to have growth-regulation role during embryo development, with possible underlying phenotypic consequences in the early post-hatching period in precocial bird

Exigências de proteína bruta e energia metabolizável em codornas de corte durante a fase de crescimento Protein and metabolizable energy requirements for meat type quail during the growing phase

Estudou-se a exigência de proteína bruta e energia metabolizável para codornas européias em crescimento, em cinco períodos experimentais, de sete dias cada. Foram utilizadas 384 codornas de ambos os sexos, com sete dias de idade em delineamento experimental utilizado inteiramente ao acaso, em esquema fatorial de 2&times;4, dois níveis de energia (2900 e 3100kcal de EM/kg de ração) e quatro níveis de proteína (22, 24, 26 e 28% de PB), com seis repetições de oito animais cada. Foram estudadas as variáveis ganho de peso (g), peso acumulado (g), consumo de ração (g) e conversão alimentar (g de ração/g de peso). Observou-se efeito linear dos níveis de proteína no primeiro período e quadrático nos demais períodos sobre o ganho de peso das aves. Os níveis de proteína foram estimados em 28,0% (2900kcal de EM/kg), 25,7% (3100kcal de EM/kg), 27,9%, 24,8% (3100kcal de EM/kg) e 23,1% (2900kcal de EM/kg) para o segundo, terceiro, quarto e quinto período, respectivamente.<br>Crude protein (CP) and metabolizable energy (ME) levels during five experimental periods of seven days each of the growing phase for European quail were determined. A total of 384 quails of both sexes were used in a completely randomized design in a 2&times;4 (energy and crude protein) factorial treatment with six replications of eight quails each. The metabolizable energy levels were 2900 and 3000kcal of ME/kg of diet and the crude protein levels were 22, 24, 26 and 28%. The analyzed variables were weight gain (g), accumulated weight (g), feed consumption (g), feed:gain ratio (g/g). Performance responses were evaluated by linear and quadratic regression of the traits on crude protein levels. Higher weight gains from the following protein and metabolizable energy levels combinations: 28.0% PB and 2900 kcal EM/kg (first period); 25.7% CP and 3100kcal ME/kg (second period); 27.9% and 2900kcal ME/kg (third period); 24.8% PB and 3100kcal/kg (fourth period) and 23.1% CP and 2900kcal/kg (fifth period)

Nível de proteína bruta para codornas de corte durante o período de crescimento Crude protein level for meat type quail during the growing period

Estudou-se a exigência de proteína bruta de codornas de corte na fase de crescimento. Foram utilizadas 288 codornas européias EV2, de ambos os sexos em delineamento experimental inteiramente ao acaso, cujos tratamentos consistiram de dietas com seis níveis de proteína bruta (23, 25, 27, 29, 31 e 33%) e quatro repetições de doze codornas por unidade experimental. Estudaram-se o ganho de peso (g), peso corporal ao final de cada período (g), consumo alimentar (g) e conversão alimentar (g/g) do nascimento ao 21ºe do nascimento ao 42º dia de idade. No 42º dia de idade, foram aleatoriamente amostradas e abatidas quatro aves por unidade experimental (dois machos e duas fêmeas), para registro dos pesos e respectivos rendimentos das carcaças, cortes nobres (coxas e peito), vísceras comestíveis (fígado, moela e coração) e gordura abdominal. Do nascimento ao 21º dia de idade, houve efeito quadrático dos níveis de proteína da dieta sobre peso corporal, ganho de peso e consumo alimentar, com pontos de máximo em 30,64, 30,65 e 29,02%, respectivamente. A conversão alimentar durante este período apresentou resposta linear, ao nível de proteína bruta da dieta. Houve efeito quadrático dos níveis de proteína bruta da dieta sobre o peso no 42º dia de idade, com máximo desempenho em 29,93%. Para o ganho de peso houve resposta linear aos níveis de proteína. Houve efeito quadrático no ganho de peso e no consumo alimentar do nascimento ao 42º dia de idade, com os pontos de máximo estimados em 29,81 e 29,11%, respectivamente. O peso corporal antes do abate, o de carcaça e o de peito foram influenciados linearmente pelos níveis de proteína bruta da dieta. Houve interação significativa nível protéico versus sexo. As fêmeas apresentaram resposta linear de rendimento de peito em relação aos níveis protéicos da dieta, enquanto o rendimento do peito dos machos não foi influenciado pela proteína da dieta. Peso corporal, rendimento de peito e peso e rendimento de fígado das fêmeas foram maiores que os dos machos. As exigências de proteína bruta estimada para o máximo ganho de peso de machos e fêmeas de codornas de corte, do nascimento ao 21º e do nascimento ao 42º dia de idade são 30,65% e 29,81%, respectivamente. A exigência para pesos de carcaça e peito é de 33,0% de proteína bruta da dieta.<br>The crude protein requirements for EV2 quail meat type genetic group during the growing period were estimated in a completely randomized experimental design, using 288 quails of both sex, six levels of crude protein (23, 25, 27, 29, 31 and 33%) and four replicates of 12 quails per experimental unit. Body weight (g), weight gain (g), feed intake (g) and feed:weight gain ratio (g/g) were recorded in each period (from hatch to 21 days and from hatch to 42 days of age). At 42 days of age, four quails were randomly sampled from each experimental unit (two males and two females) and slaughtered to record weights and yields of carcass, main cuts (thigh and breast) edible giblets (liver, gizzard and heart) and abdominal fat. Quadratic effects of crude protein level on body weight, weight gain and feed intake from hatch to 21 days of age, with maximum performances estimated for quails fed 30.64; 30.65 and 29.02% crude protein diets, respectively. Feed:weight gain ratio during this period showed a linear response in function of protein level of diet. Quadratic effect of protein level on body weight at 42 days of age was observed, with maximum performances estimated for quails fed 29.93 crude protein diets, while weight gain showed a linear response. Quadratic effects of crude protein level on weight gain and feed intake were also observed, with estimated maximum for quails fed 29.81 and 29.11% crude protein diets, respectively while body weight and carcass and breast weights were linearly affected. Higher performance were observed for quails fed diets with the highest protein level. A significant crude protein level x sex interaction was observed for breast yield, females showing linear response in function of crude protein level, while no effect on male breast yield was observed. Female body weight and breast and liver yields were higher for males crude protein. Crude protein requirements for maximum female and male weight gains are estimated in 30.65% from hatch to 21 days and 29.81% from hatch to 42 days of age while crude protein requirement for carcass and breast weights is estimated in 33%