Influence of Different Methionine Sources on Performance and Slaughter Characteristics of Broilers

Abstract

Simple SummaryThe increasing public demand for efficient, sustainably produced poultry meat with simultaneous optimization of animal welfare is calling for amendments in meat production. A starting point to meet this demand consists of complete diets for broilers with reduced crude protein content, supplemented with higher amounts of crystalline amino acids. This ensures sufficient nutritional supply and decreased nitrogen excretion for environmental relief. To optimize the performance and health, despite the drastically reduced protein content (~17.5% finisher diet), the present study compared different methionine sources (methionine hydroxy analog, DL-methionine, and L-methionine) in slightly higher dosages than found in practice, in comparison to a diet meeting the methionine requirements using methionine hydroxy analog. Methionine is the first limiting amino acid and has a significant influence on the health and growth of the animals. The results of the feeding trial showed no differences concerning general health, ileal histology, and performance data of broilers before slaughter. However, the composition of the breast meat differed significantly (highest protein content and lowest fat content in the L-methionine group), and thus provides the impetus for further research.AbstractSustainably produced poultry meat with consideration of animal health poses a challenge for broiler production. Low protein diets with high amounts of synthetic amino acids (AAs) like methionine (Met) are the consequence. In a five-week feeding trial, 360 broilers (Ross 308) assigned to four feeding groups were offered protein-reduced complete diets (starter: 20% crude protein (CP); grower: 18.5% CP; finisher: 17.5% CP), supplemented with essential AAs. The “MHA” group received DL-2-hydroxy-4-(methylthio) butanoic acid (DL-HMTBA; trade name: MHA®), groups “L” and “DL” the respective Met source in equivalent concentrations each exceeding the nutritional recommendations. “R-MHA” (“R” for “reduced”) received the minimum required level (using MHA as Met source). Performance exceeded performance goals without differences between the groups. The average feed conversion ratio (FCR) amounted to 1.35. The carcass/body weight ratio of R-MHA was significantly lower (0.782) compared to DL (0.808) and L (0.809). Breast meat of R-MHA contained significantly more fat (144 g/kg dry matter (DM)) compared to L (104 g/kg DM) and significantly lower CP content (R-MHA: 838 g/kg DM; L: 875 g/kg DM). The results indicated possible improvement in slaughter yield by protein-reduced diets supplemented with L-Met, thus recommending further research focusing on the Met influence.

Growth Performance of Broilers as Influenced by Different Levels and Sources of Methionine Plus Cysteine

“…No differences (p > 0.05) were observed for different types of amino acid on the carcass characteristics of broilers. This finding confirmed the reports of earlier researchers [31,41] who observed that the type of methionine had no effect on live weight, carcass weight, after skin removal, eviscerated weight and chest weight because L-Met is directly absorbed in the body and DL-Met, MHA is first converted into L-Met and then absorbed in the body. Also, Drazbo et al [42] found that the source of dietary methionine had no effect on carcass yield or breast muscle quality.…”

“…Therefore, the cystine deficiency results in the reduction in the recovery of breast meat and also decreases the extent of feathering. Our finding of no effects of the sources of methionine on the starter phase of broilers is supported by other researchers [22,31] who observed that L-Met and DL-Met did not affect growth performance due to conversion of DL-Met into L-Met. It seems that lower metabolization of D-amino acid due to the lower amount of D-amino acid oxidase in young broilers may reduce the utilization of higher amounts of DL-Met, which leads to metabolic stress and inhibition of body weight gain in the starter phase.…”

“…He observed no differences among L-Met, DL-Met and DL-HMTBA for weight gain and feed efficiency. No effect of methionine sources on overall growth of broiler has also been found by other researchers [21,22,31] who observed that L-Met and DL-Met had no effect on the overall phase of broilers.…”

Nutritional significance of amino acids, vitamins and minerals as nutraceuticals in poultry production and health – a comprehensive review

“…No significant differences were found in these forms on health, performance, and the quality composition of breast meat of birds. L-methionine caused the highest protein and the lowest fat content in meat (Ullirich et al 2019). Altering levels of amino acids in the diet may affect performance and health status in poultry.…”

The Response of Broiler Chickens to Dietary Soybean Meal Reduction with Glycine and Cysteine Inclusion at Marginal Sulfur Amino Acids (SAA) Deficiency

“…The deficiency or excess of methionine or cysteine in its diet affect a chicken's performance [5]. The deficiency of methionine leads to reduced growth performance, immune functioning, and increased abdominal fat proportions and feather pecking [6][7][8][9]. The methionine requirement can be fulfilled only by methionine; however, the cysteine requirement can also be satisfied with methionine.…”