Effects of dietary L-threonine and <i>Saccharomyces cerevisiae</i> on performance, intestinal morphology and immune response of broiler chickens

Abstract

The objective of this study was to investigate the effects of four dietary levels of L-threonine (0, 2.5, 5 and 7.5 g/kg) with or without Saccharomyces cerevisiae (SC) on performance, carcass characteristics, intestinal morphology and immune system of broiler chickens. A total of 360 1-d-old male broiler chicks were randomly allocated to eight treatments with three replicates of 15 birds. The experiment was done at 0 to 3 weeks (as starter phase) and 3 to 6 weeks (as grower phase). Growth performance traits including weight gain, feed intake and feed conversion ratio were recorded at the end of each week. At the end of the experiment eight birds per treatment were killed and carcass analysis was done. Sampling for blood evaluation was done on 7, 28 and 42 days of age. Results of this study indicated that use of SC did not affect feed intake, weight gain and feed conversion ratio in chicks in contrast with the L-threonine. Use of L-threonine improved feed conversion ratio and gain of birds. Carcass traits were not influenced by dietary L-threonine and SC supplements. Use of L-threonine increased the intestinal morphology parameters such as crypt depth and villi height and width in both jejunum and ileum segments. On the other hand, villi height and width and crypt depth increased in both jejunum and ileum segments when dietary L-threonine increased. Effect of SC supplement on intestinal morphology was not significant. Results of CBC (cell blood counts) parameters, such as white blood cells, red blood cells, haematocrit and haemoglobin showed that these parameters were not affected by dietary treatments. Furthermore, the immune response (antibody titre) against Newcastle disease was not affected by SC on both 26 and 42 days of age. However, use of L-threonine influenced the chicks' immune response at 42 days of age. Our results have shown that the supplementation of L-threonine as a source of dietary-threonine in combination with SC improved growth performance and intestinal morphology traits in broilers.________________________________________________________________________________

Getting Better Intestinal Health through the Addition of Yeast (Saccharomyces Cerevisiae) Combined with Threonine in Broilers Diets

“…Opposite to this results, in another experience did 2 not register changes in carcass performance in broilers fed Sc (in the same level that used here) or T (0-7.5 g/Kg food) (Rezaeipour et al, 2012). Perhaps, the different result must be attributed to the difference in Sc nature and T levels (30% vs 0.25-0.75 g/Kg feed) used in each assay.…”

“…Also, in another assay were noticed that addition of T (2.5-7.5 g/Kg food) findings, in these research, the addition of Sc alone, in the same level used on this experiment, did not modify productive variables (Rezaeipour et al, 2012). Coincidently to this results, in another research, was registered that broilers fed Sc in higher levels to use on this experience (1-3%) and noticed high Consumption but lower Weight Gain (Ahmed et al, 2015).…”

“…Opposite to this result, another researches did not register changes in intestinal morphology parameters (Villus Area and Deeper Crypt Gut) in broilers fed glucommanno-protein complex (isolated from the outer cell wall of Sc) or Sc (1-5 g/kg feed) (Brummer et al, 2010;Resinger et al, 2010;and Rezaeipour et al, 2012). Perhaps, the different results must be to nature of Sc (total) or wall cell Sc, that interact with microbiota and GALT (Geishari & Kholehipour, 2006;El Naga, 2012), and could produce different factors which act by different mechanisms, modify the balance between gut, microbiota and immunity in the broilers (Huyghebaert et al, 2011;Peralta, 2016).…”

“…In an interesting experience in broilers, was noticed that the T addition (2.5-7.5) to diets improved Growth performance and intestinal morphology traits (Rezaeipour et al, 2012).…”

Effect of Dietary Supplementation of L-Threonine on Growth Performance and Economics in Broiler Chickens

“…However, he also reported that increase in threonine requirements for broilers, raised in builtup litter environments to microbial challenges, because threonine involved in mucin formation and mucin control microbial communities and nutrient availability in the gut (5). The supplementation of L-threonine in broiler diet improved growth performance and intestinal morphology, by increasing crypt depth, villi height and width of jejunum and ileum segment in broilers (19). Similarly, the use of methionine and threonine in broiler diets above NRC recommendations, considered as a better nutritional strategy, to overcome unfavourable stress conditions by improving immune cells in tropical area.…”