Effects of Dietary Amino Acid Balance on Early Moulting in Male Broiler Breeders and Its Economic Implications on Fertility

Abstract

Early moulting in male broiler breeders is a physiological disturbance that can lead to a decline in reproductive performance and flock fertility. Nutritional imbalance, particularly in essential amino acids, has been identified as a major contributing factor. This study evaluates the role of methionine, lysine, and tryptophan in preventing early moulting and examines the economic consequences of reduced fertility in breeder operations. A combination of literature review and field observations from commercial farms in Indonesia was used to assess the correlation between amino acid profile and moulting incidence, fertility rates, and projected economic losses. The results demonstrate that optimal amino acid balance significantly reduces early moulting and supports better reproductive outcomes.

Keywords: amino acids, moulting, fertility, broiler breeders, methionine, lysine, tryptophan, economic impact

Introduction

Moulting in poultry is a natural process involving the shedding and regeneration of feathers. In male broiler breeders, however, premature or early moulting is considered pathological, often reflecting chronic stress, poor nutrition, or mismanagement. This condition not only impairs the bird’s physical appearance but also disrupts its endocrine system, resulting in reduced libido and semen quality. Among various causative factors, dietary amino acid imbalance plays a crucial role, especially methionine and lysine, which are vital for feather keratin synthesis and muscular development, and tryptophan, which influences serotonin synthesis and stress modulation.

This study aims to explore the effects of dietary amino acid balance on the incidence of early moulting in male breeders and to evaluate the consequent economic risks posed by reduced fertility in a commercial setting.

Materials and Methods

This investigation utilized a literature review approach alongside observational data from four commercial broiler breeder farms in Java, Indonesia. Male birds aged 30 to 60 weeks were monitored for signs of early moulting, fertility rate (based on candling data at 7 days of incubation), and feed formulation data, specifically the total and digestible levels of methionine, lysine, and tryptophan. The farms were categorized based on their amino acid profile into “balanced” (meeting breeder guidelines) and “imbalanced” (deficient in at least one essential amino acid).

Economic impact was estimated based on the decrease in hatching egg fertility, translated to day-old chick (DOC) production losses, using standard market price assumptions for DOC and male-to-female ratios.

Results and Discussion

Role of Amino Acids in Moulting Prevention Balanced amino acid formulations (methionine > 0.45%, lysine > 0.85%, tryptophan > 0.18%) were associated with significantly lower rates of early moulting (<7%) compared to imbalanced diets (up to 18%). Methionine and lysine directly support feather regeneration and muscle protein turnover, while tryptophan appears to mitigate behavioural stress that could trigger moulting.

Impact on Fertility Flocks experiencing early moulting showed an average fertility drop of 12-18%. Semen analysis in moulting-affected males revealed lower volume and motility. Libido score observations confirmed a reduction in mating behavior, likely due to hormonal suppression related to nutritional stress.

Economic Implications Assuming a breeder house with 10,000 hens and a fertility drop of 10%, the resulting DOC production loss (approx. 1,000 chicks/week) can translate to a financial loss of IDR 25-40 million/month, depending on market prices. Preventing early moulting via amino acid optimization could therefore significantly reduce economic risk.