The effect of genotype, choice feeding, and season on organically reared broilers fed diets devoid of synthetic methionine

Abstract

In response to the impending ban on synthetic methionine in organic poultry diets, researchers have focused on finding alternative strategies to supply this amino acid. The objectives of this study were to assess performance and carcass characteristics of broilers fed diets devoid of synthetic methionine by using 1) a slow-growing and a fast-growing genotype, 2) choicefeeding management (supplying grain and a complementary premix in 2 separate feeders), and 3) pasture access and seasonal variation. Inclusion of fish meal and high percentages of soybean meal enabled the specific genotype methionine requirement to be met. All diets were certified organic. The experiment was conducted during the grower and finisher phases in 4 different seasons: late fall, spring, summer, and early fall. Pasture access was assessed either by housing broilers on the West Virginia University Organic farm and giving them outdoor access, or by housing broilers on the West Virginia University Animal Sciences farm and giving them no outdoor access. Fast-growing genotypes were superior in performance and carcass characteristics compared with slow-growing genotypes, and choice-feeding management did not improve performance or carcass characteristics. Pasture access tended to have no effect on slow-growing broilers and decreased the performance of fast-growing broilers. Performance was decreased in late fall, likely because of cold ambient temperatures.

Response of Different Genotypes of Broilers to Lysine Supplementation Raised Under Practical Condition

“…These are probably related to the differences in the ratio of synthesis and degradation of body proteins (Fatufe et al, 2004). The present findings are consistent with Praharaj et al (2002), Sterling et al (2006), and Rack et al (2009) who observed differences in response to CP and limiting amino acids in different genotypes.…”

“…When refer to the study of Temim et al (2000), it was clear that at heat exposure changes specifically the requirements of some amino acids rather than protein requirements. Increasing utilization of the protein fraction of the diet may have caused an increase in the total heat increment metabolized (Rack et al, 2009). Therefore, improvement in weight gain with the use of low CP diet supplemented with lysine was more likely due to a reduction in heat increment produced by the metabolism of excess proteins (Saima et al, 2010).…”

The effects of an organic rearing system and dietary supplementation of an essential oil mixture on performance and meat yield of slow-growing broilers in two seasons

“…Unfortunately, the design of our experiment was not able to test the significance of the difference between the two seasons because the work was not repeated in subsequent years. In one of the recent rare examples (Rack et al, 2009), performance variables of organically reared birds were significantly affected by season and feeding management (i.e. choice feeding and lack of a methionine supplement).…”

Pengaruh Pemberian Bahan Pakan Sumber Protein Berbeda Terhadap Performans Ayam Lokal Persilangan Umur 2 – 10 Minggu Effect Of Feeding With Different Protein Sources On Performance Of Crossbred Local Chicken 2 – 10 Weeks Old

“…Beberapa penelitian menunjukkan bahwa unggas dapat memenuhi kebutuhan nutrisinya sendiri melalui sistem pemberian pakan bebas memilih. Pemberian pakan dengan sistem ini biasanya satu tempat pakan diisi dengan satu macam bahan pakan, sehingga memungkinkan unggas untuk mengkonsumsi bahan pakan yang memiliki palatabilitas tinggi dan sesuai dengan kebutuhan nutrisinya (Blair, 2008;Rack et al, 2009;Arroyo et al, 2014).…”

“…Bahan yang digunakan dalam penelitian ini adalah larutan gula untuk DOC yang baru datang, air minum, desinfektan serta vitamin, sedangkan vaksin yang diberikan adalah vaksin ND (Newcastle Desease) dan gumboro A. Rack et al (2009) yang menyatakan bahwa pada sistem pemberian pakan bebas memilih, unggas cenderung memilih bahan pakan jagung. Menurut Widodo (2010) bekatul memiliki palatabilitas yang cukup baik.…”