Effects of essential oils on milk production, milk composition, and rumen microbiota in Chios dairy ewes.

The effect of the addition of an essential oil (EO) preparation (containing a mixture of natural and nature-identical EO) on the performance of dairy ewes of the Chios breed was investigated. Eighty lactating ewes were allocated into 4 equal groups in a randomized block design, each with 4 replicates of 5 ewes housed in the same pen. The 4 groups were fed the same total mixed ration allowance, the roughage being a mixture of corn silage, lucerne hay, and wheat straw, and the concentrate based on cereals and oil cakes. Control ewes were fed their daily allowance of total mixed ration without any EO. The other 3 groups were supplemented with EO at levels of 50, 100, and 150 mg/kg of the concentrated feed, respectively. Individual milk yield was recorded daily and feed refusals were recorded on a pen basis weekly during the first 5 mo of lactation. Milk samples were analyzed for chemical composition, somatic cell count, and urea content. Rumen samples were analyzed for pH, NH(3)-N content, and protozoa, cellulolytic, hyper-ammonia-producing, and total viable bacteria counts. Results showed that inclusion of EO increased milk production per ewe, the effect being dose dependent [1.565, 1.681, 1.876, and 2.119 L/d (standard error of the difference ± 0.176) for the control, 50, 100, and 150 mg of EO/kg of concentrate diets, respectively], and thus improved feed utilization. Although the inclusion of EO did not affect milk composition, it lowered urea concentration and somatic cell count in milk samples at the highest supplementation level compared with the control. Total counts of viable and cellulolytic bacteria and protozoa were not influenced by EO supplementation; however, counts of hyper-ammonia-producing bacteria were decreased at the 2 highest supplementation levels compared with the control group. Rumen pH was not affected by EO supplementation, but rumen NH(3)-N was reduced at the highest EO supplementation level, and acetate rumen concentrations tended to decrease and propionate to increase in a dose-dependent manner. In conclusion, EO supplementation may improve feed utilization and performance of the high-yielding dairy Chios ewes; however, the underlying mechanisms leading to this improvement merit further investigation.

Performance and antioxidant status of broiler chickens supplemented with dried mushrooms (Agaricus bisporus) in their diet.

In this study, we evaluated the growth performance and antioxidant status of broiler chicken supplemented with the edible mushroom Agaricus bisporus. Ninety 1-d-old female broiler chickens randomly allotted to 3 dietary treatments were given either a nutritionally balanced basal diet or the basal diet supplemented with 10 or 20 g of dried mushroom/kg of feed for 6 wk on an ad libitum basis. Body weight, feed intake, and feed conversion ratio values were monitored weekly. To evaluate the antioxidant status of broiler chicken, refrigerated liver, breast, and thigh tissues were assayed for levels of glutathione, reduced glutathione, glutathione reductase, glutathione peroxidase, and glutathione S-transferase, as well as malondialdehyde at 6 wk of age. Results showed that dietary mushroom supplementation at both inclusion levels was accepted well by the broiler chicken and improved feed efficiency compared with the control diet. Dietary mushroom inclusion at 20 g/kg improved both growth performance and feed efficiency compared with control diet at 42 d of age. Dietary mushroom at both inclusion levels reduced malondialdehyde production in liver, breast, and thigh tissues and elevated glutathione peroxidase, reduced glutathione, glutathione reductase, and glutathione S-transferase compared with the control treatment, the effects being dose-dependent. These results suggest that A. bisporus mushroom exerts both a growth-promoting and tissue antioxidant-protective activity when supplemented in broiler chicken diets.

Aerobic and anaerobic microbiology of the immersion chilling procedure during poultry processing.

The development of treatments to reduce bacterial numbers on poultry carcasses is important for the overall hygienic quality of birds. The important washing effect of the immersion chilling procedure is discussed. Systematic monitoring of fecal bacterial indicators as well as some classic pathogens was performed at selected critical points in a water chiller ecosystem. Clostridium perfringens, fecal coliforms, Enterococcus sp., and Streptococcus sp. were found in all water chiller samples. The temperature of the chiller ecosystem varied according to location: Escherichia coli and Salmonella sp. were found at 16 degrees C, compared with the 4 degrees C location, where these species were found in lower numbers. Moreover, the psychrotrophic bacterium Pseudomonas was found only at this last location. The temperature of the water during the immersion chilling procedure was unfavorable for the growth of Campylobacter sp., whose presence was always strictly associated with a pH close to 6. Spore forms of C. perfringens were persistent in all locations and seemed to be a reliable indicator of contamination of the water chiller ecosystem.

Effects of lamb sucking on the bacterial flora of teat duct and mammary gland of ewes.

We aimed (i) to determine differences in bacterial flora of teat duct and mammary gland of ewes before and after suckling, (ii) to evaluate factors potentially affecting those. We collected samples of teat duct material and mammary secretion from 11 ewes immediately before and after sucking by lambs, as well as 120 min later. We processed samples bacteriologically and compared changes in infection by the Sign Test. We isolated bacteria from 3.5% duct and 1.5% secretion samples before suckling. Respective figures post-suckling were 10.6% and 2.0%, and 120 min later 6.8% and 1.5%. We recorded differences in infection of duct samples before and after suckling in 40 cases; bacteria were isolated before suckling from six samples, whereas after it from 34 (p < 0.001). Also, we recorded differences in samples collected after suckling and 120 min later in 12 cases; bacteria were isolated immediately post-suckling from eight samples, whereas 120 min later from four (p = 0.375). No significant changes were seen for secretion. We found neither difference between ewes with single or twin lambs, nor among stages of lactation. Mostly, we isolated staphylococci: 70% of isolates before suckling, 80% of isolates after it, 91% of isolates 120 min later. After suckling we also isolated two Mannheimia haemolytica strains. Suckling predisposes to entrance of bacteria into the teat; however, increased teat infections did not result in mammary infections. Isolation of M. haemolytica post-suckling indicates that lambs act as source of infection for this pathogen.