Journal of World's Poultry Research

35-47

Authors: Lee SA, Wiseman J, O’Neill HVM, Scholey DV, Burton EJ and Hill SE.

The objective of the current study was to investigate the mechanisms of xylanase action in a maize-soya diet and its effect on starch digestion. A total of 60 broilers were divided into 6 treatment groups; a control group without xylanase, and five other groups supplemented with xylanase (Econase XT 25; 100 g/t) from 1, 2, 3, 4 or 5 weeks before slaughter. At the end of the experiment, digesta was collected from the gizzard, upper and lower small intestine, and both caeca. Digesta pH ranged from pH 2.2-4.4, 5.9-6.6, 6.7-7.8 and 5.7-7.3 in the gizzard, upper small intestine, lower small intestine, and both caeca, respectively, with no effect of xylanase (P > 0.05). Scanning Electron Microscope (SEM) images along with total starch measurements showed the progression of starch digestion through the tract. The SEM did not show any greater disruption to cell wall material with xylanase supplementation. This suggests that xylanase was not working directly on the cell wall and provides evidence for the hypothesis that xylanase works through an indirect mechanism. Peptide YY (PYY) concentration in the blood was higher during the first few weeks of supplementation, with longer periods of supplementation nulling this effect, implying that xylanase may be acting through a prebiotic mechanism. The RT-q PCR results revealed a numerical increase in glucose transporter (GLUT2 and SGLT1) expression at 2 and 3 weeks of xylanase supplementation, respectively, which might suggest a greater absorption capacity of birds. From these results, a potential mechanism of xylanase action in maize-based diets has been proposed.

57-71

Authors: Youssef IMI, Mostafa AS and Abdel-Wahab MA

This study was conducted to evaluate the effects of probiotics and organic acids, as alternative feed additives to antibiotics, on productive performance of broilers. Two different types of probiotics varying in the microbial content were tested and organic acids blend was compared against a single organic acid (lactic acid). One hundred and ninety eight broiler chicks were randomly allocated into six treatments, each with 33 chicks. Every treatment consisted of 3 replicates with 11 birds per replicate. The dietary treatments were a control diet without any feed additives or the same control diet supplemented either with a commercial antibiotic (Maxus®G200), probiotics (Bactocell® or Biopellet-S®) or acidifiers (Salmo-Nil Dry® or lactic acid). The antibiotic was added to the diet at the rate of 0.005%, whereas the probiotics were used at 0.01%. The product Salmo-Nil Dry® was provided to the diet at a level of 0.4%, whereas the lactic acid was used at 0.20 %. It was found that the antibiotic, probiotics and lactic acid increased the body weight. All dietary supplements improved the FCR compared to the control. The additives reduced the serum cholesterol level and the pH of small intestine but did not affect the carcass yield, breast or organ weights. The feed supplements showed a numerical decrease in intestinal aerobes, fecal coliforms and E. coli counts. In addition, all additives significantly reduced total aerobic and staphylococcus counts in the carcass meat, with a numerical decrease in E. coli count. In conclusions, probiotics and acidifiers can be used as potential alternatives to antibiotics in broiler diets. No difference between the used types of probiotics was detected. Lactic acid alone seems to produce better performance results than the organic acid mixture. The effect of lactic acid produced by bacteria might be similar to that of the chemical one.

79-87

Authors: B Ngouana Tadjong R, Kana JR, Tsafack Necdem B, Yemdjie Mane DD, Mube Kuietche H, Kuiede S, Teguia A and Meimandipour A.

This study was designed to mitigate the volatile and oxidative ability of essential oils (EOs) in poultry feed using natural plant charcoal. The dietary treatments consisted of supplementing control diet (R0) with 0.01% of the mixture (1/1) of thyme and oregano EOs (RTh+or), 0.2% of Canarium charcoal without EO (R0C), 0.2% charcoal respectively enriched with 0.01% of thyme EO (R0C+Th), oregano EO (R0C+Or) and the mixture of EOs (R0C+Th+Or). Results revealed a non-significant increase in weight gain for about 5 and 6%, respectively with the mixture of the EOs without charcoal and charcoal enriched with the mixture of the EOs compared to the control (R0). The carcass yield was higher with oregano EO and the mixture of EOs compared to the other treatments. Intestinal density was lower (P < 0.05) with the mixture of the EOs compared to thyme EO alone and the control ration. Charcoal containing EOs significantly increased (P < 0.05) total protein in serum content, triglycerides, albumin, globulin and decreased serum content in creatinin, ASAT, ALAT and cholesterol. Hematological parameters were not significantly affected by the treatments. The blend of EOs associated or not to charcoal increased lactic acid bacteria count in both the ileum and the cæcum as compared to E. coli and salmonella. It was concluded that Canarium charcoal can be used to stabilize EOs in the feed for gut microbiota modulation and better growth performances of broiler chickens.