Dr Rajeeb Kumar Roy, Head Technical, RR Animal Healthcare Ltd
Dr Mandeep Maan, Poultry Expert, India.
Lysine is one of the most important essential amino acids in poultry nutrition. In maize-soybean meal–based diets (common in India and many other countries), lysine is typically the second limiting amino acid, after methionine. Because of this, adequate lysine supply is vital. PMC+2OUP Academic+2
Moreover, many nutritionists use the concept of “ideal protein” or amino acid balance — expressing the requirements of all essential amino acids (EAAs) as ratios relative to lysine. PMC+2ajhsjournal.ph+2 Thus, establishing an accurate lysine requirement becomes foundational to optimize overall protein and amino-acid nutrition.
Physiologically, lysine plays key roles: it supports protein synthesis, which is critical for muscle growth (in broilers) and for the formation of egg proteins, albumen, and other egg components (in layers and breeders). It also supports immune competence and digestive tract functioning. PMC+1
Given this, for breeder birds (both broiler-breeders and layer-breeders), having adequate lysine is essential — not only for maintenance and growth, but for egg production, egg quality, hatchability, reproductive efficiency, and overall flock health.
Lysine Requirements and Effects in Breeder Birds
Broiler Breeder Hens
- A classic study, Re-Evaluation of the Protein and Lysine Requirement for Broiler Breeder Hens reported that 32-week-old broiler breeder hens required a daily lysine intake of approximately 845 mg per hen per day (with diets varying in Lys from ~0.380% to ~0.545%) to achieve maximum egg production, egg mass, and egg content under their experimental conditions. OUP Academic
- In another fundamental work, Lysine: Amino acid requirements of broiler breeders (1998) explained that because broiler breeders are typically subjected to controlled (restricted) feed intake, the composition of the feed — especially lysine content — becomes the determinant of amino-acid supply throughout the laying cycle. OUP Academic
- More recently, the global relevance of lysine supply has been reaffirmed by studies like Effects and interactions of dietary lysine and apparent nitrogen corrected metabolizable energy on yellow‑feathered broiler breeder hens, which reported that for yellow-feathered breeder hens (a type common outside the Western commercial white-feathered strains), the optimal total dietary lysine level was estimated at 0.81% to 0.83% under certain energy (AMEn) levels for best reproductive performance and egg quality. SpringerLink+1 The study also found that lower (0.71–0.72%) lysine levels provided acceptable “breeding egg” quality, but the higher range produced optimal results. SpringerLink
- Another relevant investigation, Estimating total lysine requirement for optimised egg production of broiler breeder hens during the early‑laying period (on Ross 308 parent stock) observed that hens offered diets with total lysine at 0.55% had significantly lower egg production, egg mass and egg weight compared to hens fed 0.71%, 0.75% or 0.79% total lysine. PubMed
These studies together indicate that the lysine requirement for broiler-breeder hens depends on factors such as diet composition, feed intake, energy level (AMEn), and genetic/strain differences. Importantly, for many breeder flocks, lysine levels in the diet may need to be as high as ~0.80–0.83% (total Lys) under some contexts to support optimal egg production and reproductive performance.
Layer / Egg-Type Breeders (and Laying Hens) — Relevance for India / Tropics
While most classic lysine requirement research is on commercial broiler breeders or white-feathered layers under temperate climate, there is valuable research from India and similar tropical environments:
- A recent Indian study, Effect of Supplemental Lysine to Low Protein Diet on Production Performance, Egg Quality and Serum Biochemical Parameters of Gramapriya Laying Hens, evaluated layers fed a basal diet (14% CP, 0.60% lysine) — low in protein and lysine — and then supplemented with synthetic lysine to raise total lysine to 0.65, 0.70, and 0.75%. They observed that increasing lysine from 0.60 to 0.65% significantly improved egg production, egg mass, and feed conversion ratio; but beyond that (0.70 or 0.75%) no further improvement in those parameters. Interestingly, albumen content of eggs increased with higher lysine, while yolk content decreased. Serum protein concentration also improved with higher lysine levels. The authors concluded that ~0.70% lysine (with 14% CP) was adequate for these hens under their conditions. Indian Agricultural Research Journals
- Another Indian experiment on WLH layers (BV-300) from 25–44 weeks age by Effect of feeding different levels of lysine and protein on the performance of WLH layers found that increasing dietary digestible lysine (with two levels of crude protein, 13.36% and 15.78%) improved egg weight and egg mass; better feed efficiency was also observed with higher lysine concentration. Based on this, they estimated an optimal lysine requirement around 0.65% lysine when CP was 13.36%, or 0.63% lysine when CP was 15.78% (i.e. equivalent to ~570–599 mg Lys/day per bird). Arc Articles
- A comprehensive review of amino-acid requirements in laying hens (which includes principles applicable to breeder layers) notes that adequate lysine supports egg production, egg mass, feed conversion efficiency, as well as immune competence and gut health. PMC+1
These findings from Indian conditions show that lysine is critical even for low-input or low-protein diets often used in backyard or smallholder systems, and that modest supplementation can significantly enhance production and egg quality under tropical climates.
Why Lysine Is Especially Important for Breeder Bird Nutrition in India / Tropical Conditions
- Feed Ingredients & Limiting Amino Acids
- In India, poultry diets often rely on maize, soybean meal, and locally available ingredients (rice bran, deoiled rice bran, etc.) — which may be deficient (or marginal) in essential amino acids, especially lysine. Under such conditions, lysine is likely to be the second limiting amino acid, making supplementation or careful formulation essential. PMC+1
- Using the “ideal protein” approach, once lysine requirement is defined, other EAAs can be balanced relative to lysine — fostering cost-effective and nutritionally balanced diets suitable for local ingredients. ajhsjournal.ph+1
- Reproductive Performance and Egg Quality
- For breeder birds, egg production rate, egg mass, egg quality (albumen content, yolk ratio), hatchability — all may respond to lysine supply. The Indian study on Gramapriya hens demonstrated improved egg production, egg mass, better feed conversion, and improved albumen proportion with increased lysine. Indian Agricultural Research Journals
- Given that breeders are often managed for long-term reproduction (not just for meat), ensuring consistent lysine supply supports sustained reproductive output.
- Flexibility with Low-Protein Diets
- For small-scale or backyard poultry, high-protein feeds may be expensive. Supplementing synthetic lysine allows the possibility of reducing crude-protein content (hence cost) while still meeting essential amino-acid needs. This is particularly relevant under Indian smallholder conditions. The Gramapriya study used a low-protein (14% CP) diet with lysine supplementation. Indian Agricultural Research Journals
- This strategy can reduce feed cost, nitrogen excretion (good environment), and still maintain production — as indicated in broader literature on amino acid supplementation under reduced protein diets. ScienceDirect+1
- Adaptation to Genetic / Strain & Energy Differences
- Modern breeder strains or native/tropical genotypes may have different amino-acid needs. The yellow-feathered breeder hens study found optimal lysine levels higher than those traditionally recommended for white-feathered hens — 0.81–0.83% total lysine under certain energy (AMEn) levels. SpringerLink
- Energy levels (AMEn) in the diet interact with lysine requirement: the same lysine level may not suffice under a high-energy or low-energy diet. SpringerLink+1
- Thus, for Indian conditions (variable energy ingredients, seasonal feed ingredient shifts), breed- and diet-specific lysine evaluation may be needed.
Challenges, Risks & Considerations
While lysine supplementation and balancing are beneficial, certain caveats are warranted:
- Over-supplementation may disturb amino-acid balance: Excess lysine (especially without adjusting other amino acids such as arginine) may lead to antagonism, reducing performance or causing metabolic imbalance. This has been observed in broiler growth-phase studies. ScienceDirect+1
- Maintenance of proper amino-acid ratios: Since most amino acids needs are expressed relative to lysine under the ideal protein concept, accurate formulation is required — not just dumping lysine. Other EAAs (methionine, threonine, etc.) must be adjusted in proportion. PMC+1
- Feed intake control in breeders: In broiler breeders, feed intake is often restricted to avoid excessive body weight, which can affect amino-acid intake. As noted in classic lysine-requirement studies, when feed intake is controlled, dietary composition (including lysine) becomes even more critical. OUP Academic+1
- Variation due to strain, age, production stage, energy levels, environment: Lysine requirement is not static; it varies with bird strain (white vs yellow feathers, commercial vs native), age, laying cycle stage, dietary energy, environmental conditions (heat stress, tropical climate) and feed ingredients. This argues for local validation of lysine requirements rather than relying solely on Western commercial guidelines. SpringerLink+2Arc Articles+2
Recommendations for Breeder Bird Nutrition in India (and Tropics)
Based on the above review, the following recommendations emerge:
- Use lysine as the reference (anchor) amino acid when formulating breeder diets, and adjust other EAAs according to ideal-protein ratios.
- For broiler-breeder hens under Indian/tropical conditions (or non-white commercial strains), consider total dietary lysine around 0.80–0.83% (subject to energy level, feed intake, bird strain) — but validate with local trials.
- For low-protein diets (to reduce cost), especially in backyard or smallholder systems, supplement synthetic lysine — a diet with ~14% CP + ~0.70% Lys has been shown (in Gramapriya hens) to support reasonable egg production and quality.
- Monitor not only egg production, but egg quality (albumen ratio, shell quality), reproductive traits, bird health, and overall amino-acid balance to avoid negative effects from imbalance or over-supplementation.
- Periodically re-evaluate amino-acid requirements (including lysine) especially when you change bird strain, diet ingredients, energy density, or management practices — because requirements vary with these factors.
Conclusion
Lysine is a cornerstone amino acid in poultry nutrition — particularly for breeder birds (both broiler breeders and layer breeders). Given its role as second limiting amino acid in common maize-soy diets, and as the anchor for “ideal protein” balancing, ensuring adequate lysine supply is critical for optimal egg production, egg quality, reproductive performance, and bird health.
For India and tropical regions — where feed ingredients, energy density, bird genotypes, and management conditions vary — it is especially important to formulate diets thoughtfully, possibly supplementing lysine when necessary, and to validate requirements under local conditions. Reliable breeder performance and economic sustainability of poultry operations depend significantly on such precision in amino-acid nutrition.
Bibliography (References)
- Fisher C. Lysine: Amino acid requirements of broiler breeders. Poultry Science. 1998;77(1):124–133. OUP Academic
- Re-Evaluation of the Protein and Lysine Requirement for Broiler Breeder Hens. Poultry Science. 1995;74(3):581. OUP Academic
- Jaqueline A. Pavanini & Edney P. da Silva. Responses of Broiler Breeder Hens to Dietary Digestible Lysine, Methionine + Cystine, and Threonine. Agriculture. 2025;15(15):1685. MDPI
- (Yellow-feathered breeder) Effects and interactions of dietary lysine and apparent nitrogen corrected metabolizable energy on yellow-feathered broiler breeder hens. Journal of Animal Science and Biotechnology. 2024. SpringerLink+1
- Estimating total lysine requirement for optimised egg production of broiler breeder hens during the early-laying period. Poultry Science, PubMed. (Ross 308 parent stock). PubMed
- Panda, A.K. & Sahoo, B. Effect of Supplemental Lysine to Low Protein Diet on Production Performance, Egg Quality and Serum Biochemical Parameters of Gramapriya Laying Hens. Indian Journal of Animal Nutrition. 2025 (41(3), published Jan 18, 2025). Indian Agricultural Research Journals
- Naga Raja Kumari K., Ravinder Reddy V., Chinni Preetham V., Srinivas Kumar D., Sen A.R., Rama Rao S.V. Effect of feeding different levels of lysine and protein on the performance of WLH layers. Indian J. Anim. Res. 2017;51(5):901–905. Arc Articles
- Kopeć, P. & coauthors. (review) Amino acid requirements for laying hens: a comprehensive review. 2021. (PMC open access) — Section on Lysine’s importance for egg production, immune competence, gut health. PMC