本研究旨在比较暴露于热应激的各种鸡基因型的生长动态,低投入饮食,通过使用Gompertz模型来深入了解他们面对环境和营养挑战的能力。三项体内试验(T1:热应激,T2:低输入饮食,和T3:自由范围系统)进行,共涉及671只动物。每个试验采用五种鸡基因型:2个意大利当地品种,BiondaPiemontese(BP)和RobustaMaculata(RM),以及它们与萨索母鸡的杂交品种(BP×SA和RM×SA),和商业混合动力(罗斯308)。单独鉴定了一天大的雄性小鸡,并且将5种基因型随机分配到不同的挑战性条件下:T1涉及2种环境温度(热中性与高温);T2涉及2种饮食(标准与低输入);T3涉及2个饲养系统(常规与自由范围)。鸡从到达到屠宰,每周称重一次,并使用Gompertz模型建立生长曲线。来自不同基因型的鸡根据其成熟度在不同年龄被屠宰。在所有的试验中,挑战性条件显着降低了罗斯鸡的成年体重(A;-31.0%)和最大生长速率(MGR;-25.6%)。相比之下,在T1和T2,当地品种和杂交品种的主要生长曲线参数没有观察到显著变化,在自由放养条件下,这些基因型的A和MGR甚至增加。杂交育种可有效提高BP的A和MGR(BP×SA为30.5%),以及提高RM的早熟性和MGR(RM×SA+19.5%)。我们的发现强调了Gompertz模型作为评估鸟类适应性的工具的有效性,并证实了当地品种和杂交品种适应不同挑战的更大能力。总之,我们的方法学方法可用于选择最适合环境背景的基因型,并确认杂交在增强复原力和可持续性方面的潜在优势.
The present study aimed to compare the dynamics of growth of various chicken genotypes exposed to heat stress, low-input diets, and free-range farming by using Gompertz model to gain insights into their capabilities to face environmental and nutritional challenges. Three in vivo trials (T1: heat stress, T2: low-input diets, and T3: free-range system) were conducted, involving a total of 671 animals. Five chicken genotypes were employed in each trial: 2 Italian local breeds, Bionda Piemontese (BP) and Robusta Maculata (RM), along with their crossbreeds with Sasso hens (BP×SA and RM×SA), and a commercial hybrid (Ross 308). One-day-old male chicks were individually identified, and the 5 genotypes were randomly allocated to different challenging conditions: T1 involved 2 environmental temperatures (thermoneutral vs. high temperature); T2 involved 2 diets (standard vs. low-input); T3 involved 2 rearing systems (conventional vs. free-range). The chickens were weighed once a week from their arrival until slaughtering, and the data were used to build growth curves using the Gompertz model. Chickens from different genotypes were slaughtered at varying ages based on their maturity. In all trials, the challenging conditions significantly reduced adult body weight (A; -31.0%) and maximum growth rate (MGR; -25.6%) of Ross chickens. In contrast, in T1 and T2, no significant changes were observed in the main growth curve parameters of local breeds and crossbreeds, while under free-range conditions, there was even an increase in the A and MGR of these genotypes. The
crossbreeding was effective in increasing A and MGR of BP (+30.5% in BP×SA), as well as in improving the precocity and MGR of RM (+19.5% in RM×SA). Our findings highlight the effectiveness of the Gompertz model as a tool for evaluating birds\' adaptability and confirm the greater ability of local breeds and crossbreeds to adapt to different challenges. In conclusion, our methodological approach could be used to choose the genotype most suited to the environmental context and confirm the potential advantages of
crossbreeding for enhancing resilience and sustainability.