Short-chain fatty acids such as butyrate are considered potential alternatives to antibiotic growth promoters. The efficacy of butyric acid on performance and carcass characteristics of broiler chickens was tested in two studies. The effect of dietary butyrate on the ability to withstand coccidial oocyte challenge also was investigated. In experiment 1, male broiler chickens were fed diets supplemented with 0 or 11 ppm virginiamycin or 0.2 or 0.4% butyric acid (as mono-, di-, and triglyceride). In experiment 2, broilers were fed bacitracin methylene disalicylate or 0.1 or 0.2% butyric acid. In another trial, birds vaccinated against coccidiosis were challenged with oocytes at 21 d and examined 6 d later. In experiment 1, diet treatments had no effect on body weight gain. Feed intake of the birds fed 0.4% butyric acid was decreased (P < 0.01) compared with birds fed the nonmedicated diet during the starter period, whereas birds fed 0.2% butyric acid had similar feed intake to the control birds. In experiment 2, diet treatments did not affect the performance of broiler chicks while carcass weight and breast meat yield increased (P < 0.01) in birds fed 0.2% butyric acid. With oocyte challenge, birds that had received butyric acid before challenge showed higher growth rate following the challenge compared with birds that received nonmedicated feed. Bacitracin decreased (P < 0.05%) duodenal villi crypt depth, whereas villus length was similar in birds fed butyric acid or the nonmedicated control diet. These results show that 0.2% butyric acid can help to maintain the performance and carcass quality of broilers, especially in vaccinated birds challenged with coccidiosis.

. M. 2004. Impact of feeding blends of organic acids and herbal extracts on growth performance, gut microbiota and digestive function in newly weaned pigs. Can. J. Anim. Sci. 84: 697-704. One hundred eighty newly weaned pigs were used to investigate effects of feeding organic acids and herbal extracts on growth performance, gut morphology and microbiota, and immune response in newly weaned pigs during a 4-wk period. There were five dietary treatments: control, Acid 1 (acetic, propionic, phosphoric and citric acid; 1.1% inclusion), Acid 2 (Acid 1 + 1.0% lactic acid), herbal extracts (0.75% inclusion; containing cinnamon, thyme and oregano extract), and antibiotic (110 ppm lincomycin). As compared to the control, pigs on antibiotic and Acid 2 showed higher (P < 0.05) ADG only during week 2 post-weaning, whereas pigs on herbal extract showed lower (P < 0.05) ADG only during week 3 post-weaning. Fecal coliform counts were lower (P < 0.08) in pigs on Acid 1 and 2 on day 4 post-weaning and in pigs on antibiotic and herbal extract on day 14 post-weaning. Fecal lactobacilli counts were lower (P < 0.05) in pigs on antibiotic on day 14 post-weaning. Based on PCR-DGGE, treatment influenced the composition of gut microbiota. The pH of the colon was lower (P < 0.05) in pigs on acid treatments and serum IgG was lower (P < 0.05) in pigs on antibiotic. Dietary treatment did not affect (P > 0.10) intestinal morphology. These results show that the inclusion of antibiotic in the diet reduced the proliferation of both potentially harmful coliform bacteria and potentially beneficial lactobacilli in the pig's gut, while herbal extract and organic acids appeared to reduce the proliferation of coliform bacteria. Blends of organic acids can serve as an alternative to in-feed antibiotics during the first few weeks post-weaning for pigs. . Comparativement aux sujets du traitement témoin, les porcelets recevant l'antibiotique et le mélange d'acides n 2 affichaient un GQM plus élevé (P < 0,05) durant la deuxième semaine suivant le sevrage seulement alors que ceux recevant le mélange d'extraits d'herbes présentaient un GQM plus faible (P < 0,05) la troisième semaine suivant le sevrage uniquement. Le nombre de coliformes fécaux était plus bas (P < 0,08) chez les porcelets recevant les deux mélanges d'acides quatre jours après le sevrage et chez ceux recevant l'antibiotique et le mélange d'extraits d'herbes le 14 e jour suivant le sevrage. La population de lactobacilles fécaux était plus faible (P < 0,05) chez les animaux recevant l'antibiotique le 14 e jour suivant le sevrage. Selon les résultats de la PCR-DGGE, le traitement influe sur la composition de la microflore intestinale. Le pH est plus faible (P < 0,05) dans le côlon des animaux recevant un mélange d'acides et la concentration d'IgG dans le sérum était plus faible (P < 0,05) chez les porcelets recevant l'antibiotique. Le traitement alimentaire n'affecte pas (P < 0,05) la morphologie des intestins. Ces résultats indiquent que l'inclusion d'un antibiotique à la ration ralentit la prol...

Two experiments were carried out with broiler breeders (experiment 1) and laying hens (experiment 2) to study the effects of Se sources, in interaction with dietary level of Se or dietary fats on performance, Se incorporation into tissues (blood, liver, breast muscle, and egg) and eggs, hatchability, and glutathione peroxidase (GPX) activities in tissues and blood. Both experiments involved a 3 x 2 factorial arrangement of 3 Se sources (selenite, Se yeast, or B-Traxim Se) and either 2 levels of each source (0.1 or 0.3 mg/kg) or 2 fats (fresh or oxidized). Egg production was not affected by Se source or dietary fat in both experiments. Egg production was greater (P < 0.01) in breeder hens fed 0.3 mg/kg of Se in experiment 1. Hatchability of eggs from hens fed 0.1 mg/kg of Se was lower (P < 0.05) in hens fed Se yeast, whereas from hens fed 0.3 mg/kg of Se, it was comparable across treatments. Selenium in egg, liver, and breast muscle was greater (P < 0.01 or <0.05) in hens fed the greater concentration of Se. Eggs from breeder hens fed organic Se sources had greater (P < 0.01) Se content than those of inorganic source. Egg albumen from breeder fed Se yeast had the greatest Se (P < 0.01), whereas egg yolk from hens fed B-Traxim Se had the greatest Se (P < 0.05). These parameters were affected by interaction between dietary Se level and source (P < 0.01 or < 0.05). Selenium contents in liver and breast muscle were greater (P < 0.01) in hens fed Se yeast compared with hens fed other sources of Se. In experiment 1, liver GPX was greater (P < 0.01) in hens fed selenite or Se yeast, whereas plasma GPX was greater (P < 0.01) in hens fed selenite compared with B-Traxim Se or Se yeast. Supplementation with oxidized fat increased (P < 0.05) GPX in blood and liver. B-Traxim Se decreased (P < 0.05) malondialdehyde content in breast muscle of layers. It is concluded that broiler breeders require supplementation of 0.3 mg/kg of Se, and that there are numerous measurable advantages in using organic rather than inorganic sources for both breeders and layers.

The antimicrobial activities of n-butyric acid and its derivatives against Salmonella Typhimurium and Clostridium perfringens were studied. n-Butyric acid and its derivatives (monobutyrin and a mixture of mono-, di-, and tri-glycerides of butyric acid) were added at different concentrations (ranging from 250 to 7,000 mg/kg to a media inoculated with either Salmonella Typhimurium or C. perfringens. The antimicrobial activity of butyric acid against C. perfringens was measured at 2 bacterium concentrations and 2 inoculations involving ambient aerobic or anaerobic conditions. The most effective antimicrobial activity for Salmonella Typhimurium was observed with n-butyric acid, with 90% inhibition rate at a concentration of 1,500 mg/kg. Although minimal inhibition for Salmonella Typhimurium was observed with butyric acid glycerides, lipase addition to a mixture of mono-, di-, and triglycerides of butyric acid increased (P < 0.01) antimicrobial activity of these derivatives. Antimicrobial activity of butyric acid and its derivative against C. perfringens was higher when using a moderate initial inoculation concentration (10(5)) compared with a higher initial concentration (10(7)) of this bacterium. At a lower inoculation of C. perfringens (10(5)), >90% inhibition rate by all butyric acid glycerides was observed with prior aerobic inoculation at 2,000 mg/kg, whereas using anaerobic inoculation, only 50% monobutyrin maintained >90% inhibitory effect at 3,000 mg/kg. The antimicrobial effect of monobutyrin against C. perfringens was generally higher (P < 0.01) for 50% monobutyrin than for 100% monobutyrin. Either a mixture of butyric acid derivatives or 50% monobutyrin decreased (P < 0.01) C. perfringens in a media containing intestinal contents whereas only 50% monobutyrin decreased (P < 0.01) Salmonella Typhimurium within a media containing cecal contents from mature Leghorns. These results show that n-butyric acid and 50% monobutyrin could be used to control Salmonella Typhimurium or C. perfringens in poultry species.

An experiment employing a factorial arrangement of two levels (3.0 and 4.0%) of Ca, two levels (0.15 and 0.25%) of nonphytate phosphorus (NPP), and two levels (0 and 300 U/kg diet) of microbial phytase was carried out with 960 ISA-brown layers from 21 to 41 wk of age. There was a significant interaction between NPP level and phytase for egg production. High NPP level and phytase supplementation increased egg production only in the second 10-wk period (31 to 41 wk). High NPP and low Ca increased feed intake, and a significant interaction between levels of NPP and Ca was observed in the first 10 wk. High NPP improved feed efficiency only in the second 10-wk period. Low NPP improved egg specific gravity and eggshell thickness but decreased Haugh units in the first 10-wk period; high NPP decreased the percentage of broken and soft-shell eggs in the second period. Low Ca decreased egg specific gravity, eggshell strength, and eggshell thickness in both periods and increased Haugh units in the second 10-wk period. Phytase supplementation decreased the percentage of broken and soft-shell eggs. High NPP increased fiber availability but decreased Ca availability. High Ca decreased Ca availability, whereas phytase increased availability of dry matter, fiber, and P. High NPP increased retention of P and Fe but also increased excretion of P. High Ca decreased retention of Zn and Fe. Phytase supplementation increased P retention, resulting in decrease of P excretion. In conclusion, supplementation of microbial phytase at a level of 300 U per kg diet of laying hens can improve egg production, decrease broken and soft egg production rate, and P excretion. The effects of phytase supplementation are significantly modified by the level of Ca and NPP.