Plasma Thyroid Hormone Concentrations and pH Values of Some GI-Tract Segments of Broilers Fed on Different Dietary Citric Acid and Microbial Phytase Levels

Abstract

Problem statement: An experiment was conducted to study the effect of microbial phytase supplementation and citric acid on thyroid activity, relative weight of lymphoid organs and pH values of some GI-tract segments in broiler chickens fed corn-soybean meal based diets. Approach: The data was analyzed using a Randomized Complete Block Design (RCBD) with factorial arrangement of 3×3, three levels of citric acids (0, 3 and 6%) and three levels of phytase (0, 500 and 1000 IU kg). There were three replicates (with ten chicks in each replicate) for each treatment. A total of 270 Ross 308 broiler chicks were used. Results: Addition of citric acid to diets caused significant decrease in pH values of crop, gizzard, duodenum, jejunum and ileum (p<0.05) and caused significant increase (p<0.01) in plasma triiodothyronine (T 3 ) concentration, T 3 :T 4 ratio and relative weight of bursa and thymus, but had no significant effect on thyroxin (T 4 ) concentrations. Microbial phytase significantly increased relative weight of thymus (p<0.01), but had no significant effects on thyroid gland activity, relative weight of bursa and values of pH in different parts of the GI-tract. Conclusion: Broiler chicks fed on acidifiers diets had better immune response resistance that lead to immunological advances. Also, decreasing pH in GI-tract by CA caused a beneficial effect in the inhibition of intestinal bacteria competition.

Influence of limestone and phytase on broiler performance, gastrointestinal pH, and apparent ileal nutrient digestibility

“…In the current experiment, dietary inclusion of 5,000 FTU/kg of phytase influenced gastrointestinal pH. Supplementation of a microbial phytase at 250, 500, or 1,000 FTU/kg did not influence stomach pH in 32kg pigs (Radcliffe et al, 1998), gastrointestinal pH in 42-d-old broilers (Nourmohammadi et al, 2011), or ileal pH in 21-d-old broilers (Akyurek et al, 2011). However, feeding 1,000 FTU/kg of phytase significantly increased fecal pH in 53-kg pigs (Metzler et al, 2008).…”

Dietary organic acids for broiler chickens: a review

“…(2008), Panda et al . (2009a), and Nourmohammadi et al . (2011) reported a significant pH reduction in the duodenum, whereas other studies found no significant pH reductions in the duodenum.…”

Effects of citric acid supplementation on growth performance, intestinal morphology and microbiota, and blood parameters of geese from 1 to 28 days of age

“…Studies showed the addition of CA in poultry diet contributed to decreasing the counts of pathogenic intestinal bacteria ( Tollba, 2010 ; Elnaggar and Abo El-Maaty, 2017 ; Fikry et al., 2021 ). Besides the antimicrobial activity, CA also reduce the pH of gastro-intestinal tract content ( Nourmohammadi et al., 2011 ; Fikry et al., 2021 ), improve the morphometry of small intestine ( Nourmohammadi and Afzali, 2013 ), and enhance the feed nutrients digestibility ( Nourmohammadi et al., 2012 ; Fikry et al., 2021 ). Furthermore, supplementing CA in low nutrient diets may compensate for the performance losses of broilers ( Das et al., 2012 ; Islam et al., 2021 ).…”