heat-related stress has become a serious problem in poultry industry along with the global temperatures rise. heat stress causes detrimental effects on physiology, immunology and microbiology resulting in abnormalities and impaired performances of birds. several nutritional strategies have been conducted to counteract the detrimental effects of heat stress in poultry, including dietary supplementation of probiotics. this strategy has been proposed to ameliorate the intestinal ecosystem, physiological conditions and immune system, leading to the improved performance and health of birds subjected to heat stress. This review presents the potential benefits of probiotics against heat stress in poultry from the viewpoint of intestinal microbial ecology, morphology and structure, physiological conditions, immune system and production performances. the possible mechanisms through which probiotics may give beneficial impacts on heat-stressed birds are also discussed along with the data reporting the possible drawbacks of using probiotics in heat-stressed poultry.

Abstract. Dietary supplementation of additives has recently been part of strategies to deal with the detrimental effects of heat stress (HS) on the performance and carcass traits in broiler chicks. This study aimed to investigate the effect of dietary supplementation with the fungi Rhizopus oryzae or Chrysonilia crassa on growth, blood profile, intestinal microbial population and carcass traits in broiler chicks subjected to HS. R. oryzae and C. crassa are filamentous fungi isolated from the ileum of indigenous Indonesian chickens which exhibited probiotic and antioxidant properties. Two hundred and forty 21-day-old male broiler chicks were randomly allotted into six groups, including birds reared under normal temperature (28 ± 2 • C) (CONT), birds reared under HS conditions (35 ± 2 • C) (HS-CONT), birds reared under HS and provided with commercial anti-stress formula (HS-VIT), birds reared under HS and provided with R. oryzae (HS-RO), birds reared under HS and provided with C. crassa (HS-CC) and birds reared under HS and provided with rice bran (HS-RB). Body weight gain was highest (P < 0.01) and lowest (P < 0.01) in CONT and HS-CONT birds, respectively. The heart was heavier (P < 0.05) in CONT than in HS-CONT and HS-VIT birds. CONT birds had heavier duodenum (P < 0.05) and jejunum (P < 0.01) than other birds. Eosinophils was higher (P < 0.05) in HS-CC than in other birds. Lowdensity lipoprotein (LDL) was higher (P < 0.05) in HS-CONT than in CONT, HS-VIT and HS-CC birds. Total triglyceride was highest (P < 0.05) and lowest (P < 0.05) in HS-RB and HS-RO birds, respectively. Alanine aminotransferase (ALT) was higher (P < 0.05) in HS-CONT than in other HS birds. Total protein was lowest and highest (P < 0.05) in CONT and HS-CONT birds, respectively. Albumin was higher (P < 0.05) in HS-CONT and HS-VIT than in HS-RO birds. Globulin was lower (P < 0.05) in CONT than in HS-CONT, HS-VIT and HS-RB birds. Uric acid was lower (P < 0.05) in CONT than in HS-CONT and HS-VIT birds. The 2,2 -azino-bis(3-ethyl-benzthiazolin-6-sulfonic acid) (ABTS) percentage inhibition values of the serum were higher (P < 0.01) in CONT, HS-CONT and HS-VIT than those in HS-RO, HS-CC and HS-RB birds. In conclusion, dietary supplementation of C. crassa decreased serum LDL concentration and ALT activity and improved antioxidant status of broiler subjected to HS. Supplementation with C. crassa seemed beneficial in improving physiological conditions of HS birds.

The experiment was carried out to investigate the effect of turmeric extract on blood parameters, feed efficiency and abdominal fat content in broilers. A total of 100 mixed-sexes Lohman chicks were used in the experiment set up with completely randomized design of 5 different doses of turmeric extract given orally start from day-15 to day-35. The chicks given no turmeric extract were used as a control (T0), whereas T1, T2, T3 and T4 were the chicks given turmeric extract of 200, 400, 600 and 800 mg/kg-live BW, respectively. Hemoglobin values of broilers given turmeric extract 800 mg/kg-live BW was significantly higher (p<0.05) at week-3 and week-4, but not at week-5, compared to broilers given turmeric extract with lower doses or control group. Turmeric extract did not affect significantly (p>0.05) the concentration of erythrocytes, the levels of hematocrit as well as FCR and abdominal fat content of broiler. Turmeric extract seemed to be able to improve the digestion and metabolism (of fat) resulted in enhanced production of hemoglobin in broilers. The hypolipidemic effect of turmeric that could hamper its potential to promote the growth of broilers per se might explain why turmeric could not improve the feed efficiency of broiler.

Cassava pulp is an energy-rich by-product of the tapioca industry, and is known as a good media for growing filamentous fungi. It may therefore be not only an alternative to maize in poultry diets, but also a carrier for beneficial fungi. This study aimed to investigate the effects of dietary inclusion of the fungus Acremonium charticola (grown in A. charticola-fermented cassava pulp) (AC-FCP), with or without antibiotic growth promoters (AGPs), on growth performance, nutrient digestibility, and meat quality of broiler chicks. A total of 192 broiler chicks were assigned to one of four dietary treatments, including a control diet (maizesoybean-meal-based diet), control diet + AGPs (neomycin) (0.0003% of diet), AC-FCP diet (containing 16% of AC-FCP), and AC-FCP + AGPs. There was a tendency towards lower feed costs per kilogram live bodyweight (BW) gain in AC-FCP and AC-FCP + AGPs than in the control and control + AGPs birds. The birds fed the AC-FCP diet had greater spleen relative weight than the control and AC-FCP + AGPs birds. The birds fed diets containing AC-FCP and AC-FCP + AGPs had heavier ileum and caecum, and tended to have smaller livers than the control and control + AGPs birds. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) percentage inhibition values were lowest and highest in the AC-FCP and control birds, respectively. The breast meat of the control birds had lower crude protein content than that of other experimental groups. In conclusion, dietary inclusion of AC-FCP reduced the feed cost per kilogram live weight gain of broiler chicks. The fungus A. charticola (grown in AC-FCP) seems to play an important role in increasing the relative weight of spleen, ileum and caecum, alleviating oxidative stress, and increasing the protein content of breast muscle of broiler chicks.

Spirulina platensis is a good candidate as an in-feed antibiotics substitute for broilers. However, its use seems impractical owing to its high price, especially when being administered throughout the whole rearing period. This study aimed to investigate the effects of feeding duration of S. platensis on growth, haematological parameters, intestinal microbial population, and carcass traits of broiler chicks. A total of 288 one-day-old broiler chicks were randomly allotted to one of four groups, including control (basal diet with 0.04% zinc bacitracin) (CONT) and birds receiving basal diet supplemented with 1% of S. platensis for the first seven days (SP-7), for 21 days (SP-21), and for 35 days (SP-35). In this study, treatments had no significant effect on the growth performance of broilers. The caecum relative weight was significantly higher in SP-35 than in CONT and SP-21 birds. The values of haemoglobin, erythrocytes, and haematocrit were significantly lower in SP-35 than in other birds. Compared with CONT, SP-35 birds had significantly lower numbers of leukocytes, lymphocytes, and a lower number of eosinophils. The numbers of coliform were significantly lower in the ileum of SP-21 than in CONT and SP-7 birds. In the caecum, coliform tended to be lower in SP-21 than in other birds. There was no significant difference in the carcass traits of broilers across the groups. In conclusion, the administration of S. platensis for the first 21 days of broilers' life resulted in similar or even better responses than administration of S. platensis or in-feed antibiotics throughout the rearing period. ______________________________________________________________________________________