ABSTRACT To study the antimicrobial and uric acid-preserving activity of pine bark tannin on poultry litter composting, antibiotic-free wood chip-based poultry litter was distributed (11 g) to 50-mL conical centrifuge tubes and immediately amended with 1.3 mL0.4 M sodium phosphate buffer (control) or with 1.3 mL condensed tannins from pine bark (Pinus palustris; 9 % tannin wt/vol in water). All tubes (n = 3 tubes/treatment) were inoculated with a novobiocin and naladixic acid-resistant Salmo-nella typhimurium (STNN) to achieve 3.0 log10 CFU/g and incubated at 37oC for 3 days to simulate an initial compost period. Wildtype E. coli and the challenge STNN strain as well as concentrations of ammonia, uric acid and urea were measured on days 0 and 3. Pine bark tannin treatment decreased (p<0.01) STNN populations in the litter by 0.6 log units compared to the controls. Wildtype E. coli populations were unaffected by tannin treatment (p>0.05). Ammonia accumulation decreased (p<0.01) 23% in tannin-treated litter compared to the control (2.8 ± 0.1 µmol/g). Conversely, the residual uric acid concentration was 1.6-fold higher (p=0.02) in litter treated with the pine bark tannin than in the control litter. Urea concentrations were unaffected by tannin treatment (p>0.05). Results suggest that pine bark tannin treatment may preserve uric acid and reduce ammonia volatilization in composted litter while aiding Salmonella control.

Abstract Solid-state fermentation can be used to produce feeds for ruminants, which can provide an enriched population of yeasts to improve ruminal fermentation. Fermentation of apple bagasse was performed to obtain a yeast-rich product, with the objective of isolating, identifying, and characterizing yeast strains and testing their capability to enhance in vitro ruminal fermentation of fibrous feeds. Yeasts were isolated from apple bagasse fermented under in vitro conditions, using rumen liquor obtained from cannulated cows and alfalfa as a fibrous substrate. A total of 16 new yeast strains were isolated and identified by biochemical and molecular methods. The strains were designated Levazot, followed by the isolate number. Their fermentative capacity was assessed using an in vitro gas production method. Strain Levazot 15 (Candida norvegensis) showed the greatest increase in gas production (p < 0.05) compared with the yeast-free control and positively affected in vitro ruminal fermentation parameters of alfalfa and oat straw. Based on these results, it was concluded that the Levazot 15 yeast strain could be potentially used as an additive for ruminants consuming high-fiber diets. However, further studies of effects of these additives on rumen digestion, metabolism, and productive performance of ruminants are required.

ABSTRACT Poultry farmers in the southeastern of Mexico consider that the productivity of the hens that comes from rearing on floor has a higher productive performance than reared hens in cages, mainly due to higher percentage of egg laying and lower mortality. The aim of this study was to evaluate the productive performance of the laying hen in relation to the type of rearing. A total of 79680 pullets Bovans White of 17 weeks of age were housed in cages with five pullets cage-1 (405 cm2pullet-1). They were divided in two treatments according to their type of rearing (floor vs cage) with four replicates. The study period was from week 20 to week 40 of age. The variables evaluated were daily (%) and cumulative mortality (%), egg production (%), egg weight (g), feed intake (g pullet d-1), cumulative feed intake (g pullet-1), daily and cumulative egg mass, number of eggs per hen housed, egg loss (%) and productivity index. The variables were analyzed using a randomized block design. It was observed that daily and cumulative mortality, feed intake and egg loss was higher (p< 0.05), while the number of eggs per hen housed and productivity index (p< 0.05) was lower for hens in cages. We conclude that it is possible to associate detriments in the productive performance of laying hens based on the type of housing during its growth phase.