Effects of mannan oligosaccharide and <i>Curcuma xanthorrhiza</i> essential oil on the intestinal morphologyand stress indicators of broilers subjected to cyclic heat stress

An experiment was carried out that was intended to explore the growth performance, nutrient retention, and heat stress biomarkers of finishing broilers under cyclic heat stress (HS) as modulated by the supplementation of mannan oligosaccharide (MOS) and <i>Curcuma xanthorrhiza</i> essential oil (CXEO). Two hundred and forty 21-day-old Ross 308 male broilers were allocated to four experimental treatments, each of which was replicated six times with 10 broilers per replicate. The diets included a control (CON), CON + 5 g of MOS kg⁻¹, CON + 400 mg of CXEO kg⁻¹ of feed, and CON + 5 g of MOS kg⁻¹ + 400 mg of CXEO kg⁻¹. From day 22 to 42, birds were subjected to cyclic HS by exposing them to 33 °C for 10 h (from 07:00 to 17:00 LT) and 22 °C from 17:00 to 07:00. Dietary treatments did not have an effect on average daily feed intake, feed conversion ratio, the duodenal histomorphology, and relative visceral weights. Body weight, average daily gain, villus length, crypt depth, and the villus-length-to-crypt-depth ratio in the jejunum were significantly increased in birds fed MOS or MOS + CXEO diets (<i>p</i>&thinsp;&lt;&thinsp;0.05). The relative bursa weight of the control birds was lower (<i>p</i>&thinsp;&lt;&thinsp; 0.05) compared to those fed the MOS diet. Compared with CON, dietary treatments reduced corticosterone and creatine kinase levels, the heterophile-to-lymphocyte ratio, and mRNA levels of heat shock protein 70 in the breast muscle and jejunum (<i>p</i>&thinsp;&lt;&thinsp;0.05). It was concluded that dietary supplementation of either MOS or CXEO alone or in combination may reduce some of the harmful effects of HS in broiler chickens

Heat shock protein 70 mRNA expression and immune response of heat-stressed finishing broilers fed propolis (bee glue) supplementation

This 2&times;2 factorial experiment investigated the efficacy of propolis (bee glue; BG) in ameliorating heat-stress-induced impairment of growth performance, the hematological profile, intestinal morphology, and biomarkers of heat stress in broilers. Two hundred and forty 21-day old Ross 308 male broiler chicks were allocated to four experimental treatments in six replicates of 10 birds each. The main factors were composed of diet (basal diet or addition of 3 g kg⁻¹ of BG) and temperature (thermoneutral or heat stress). Broilers subjected to heat stress had reduced average daily gain (ADG) and average daily feed intake (ADFI); a higher heterophil level and heterophil-to-lymphocyte ratio, and a lower lymphocyte level; upregulated mRNA expression of 70 kDa heat shock protein (HSP70) levels in heart, kidney, and breast muscle; and shorter jejunal villus height, deeper crypt depth, and a lower ratio of villus-height-to-crypt-depth compared with those broilers raised in thermoneutral conditions. Supplemental BG increased ADG, jejunal villus height, and the villus-height-to-crypt-depth ratio and decreased the feed-to-gain ratio and creatine kinase and lactate dehydrogenase levels in breast muscle compared with the birds who received control diets. The inclusion of BG in diets significantly decreased the mRNA expression of HSP70 levels in heart, kidney, and breast muscle in birds subjected to heat challenge. These results indicate that the BG-supplemented diet was effective in partially ameliorating adverse effects in resistance to heat stress in broiler chickens