Browsing by Author "Burke JL"

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    Dietary Supplementation of Yeast Culture Into Pelleted Total Mixed Rations Improves the Growth Performance of Fattening Lambs
    (Frontiers Media S.A., 2021-05) Song B; Wu T; You P; Wang H; Burke JL; Kang K; Yu W; Wang M; Li B; He Y; Huo Q; Li C; Tian W; Li R; Li J; Wang C; Sun X
    There is a growing interest in the use of yeast (Saccharomyces cerevisiae) culture (YC) for the enhancement of growth performance and general animal health. Grain-based pelleted total mixed rations (TMR) are emerging in intensive sheep farming systems, but it is uncertain if the process of pelleting results in YC becoming ineffective. This study aimed to examine the effects of YC supplemented to pelleted TMR at two proportions of corn in the diet on animal performance, feed digestion, blood parameters, rumen fermentation, and microbial community in fattening lambs. A 2 × 2 factorial design was adopted with two experimental factors and two levels in each factor, resulting in four treatments: (1) low proportion of corn in the diet (LC; 350 g corn/kg diet) without YC, (2) LC with YC (5 g/kg diet), (3) high proportion of corn in the diet (HC; 600 g corn/kg diet) without YC, and (4) HC with YC. Fifty-six 3-month-old male F2 hybrids of thin-tailed sheep and Northeast fine-wool sheep with a liveweight of 19.9 ± 2.7 kg were randomly assigned to the four treatment groups with an equal number of animals in each group. The results showed that live yeast cells could not survive during pelleting, and thus, any biological effects of the YC were the result of feeding dead yeast and the metabolites of yeast fermentation rather than live yeast cells. The supplementation of YC resulted in 31.1 g/day more average daily gain regardless of the proportion of corn in the diet with unchanged feed intake during the 56-day growth measurement period. The digestibility of neutral detergent fibre and acid detergent fibre was increased, but the digestibility of dry matter, organic matter, and crude protein was not affected by YC. The supplementation of YC altered the rumen bacterial population and species, but the most abundant phyla Bacteroidetes, Firmicutes, and Proteobacteria remained unchanged. This study indicates that YC products can be supplemented to pelleted TMR for improved lamb growth performance, although live yeast cells are inactive after pelleting. The improved performance could be attributed to improved fibre digestibility.
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    The effects of increasing concentrations of Trichanthera gigantea leaves in pellets on the nutritive value and short-term intake of diets of grass plus pellets offered to lambs reared under tropical conditions in the Caribbean
    (Centro Internacional de Agricultura Tropical, 2021-09) Jack HA; Cranston LM; Burke JL; Knights M; Morel PCH
    There is currently limited information on the benefits of increasing the concentration of Trichanthera gigantea leaves in pelleted diets offered to lambs reared under tropical conditions in the Caribbean. Twelve crossbred Barbados Blackbelly rams aged 5 months were used to determine the effects of increasing the concentrations of T. gigantea in pelleted diets, on the nutritive value and intake of grass forage plus pellets offered to lambs. Animals were randomly assigned to a basic diet (4 kg) of chopped Cenchrus purpureus plus 1 of 6 pelleted diets (500 g) comprised of either 100% intact commercial pellets or a pelleted mixture of ground commercial pellets and ground (dry fallen) T. gigantea leaf in the following ratios (T. gigantea leaves:ground commercial pellets): 20:80 (T20); 40:60 (T40); 60:40 (T60); 80:20 (T80); and 100:0 (T100). Total intakes of forage and pellets (TPI) were measured at the end of each day during a period of 7 days, and the average daily nutrient intakes of the different treatment diets were calculated. Overall, there was no significant difference in the intakes of pellets containing 0 to 80% T. gigantea leaves (P>0.05) but intakes of pellets comprising 100% T. gigantea leaves were significantly lower (P<0.0001). Both CP and soluble protein intakes declined progressively as the percentage of T. gigantea leaves in the pellets increased. While level of T. gigantea leaves in pellets fed to lambs did not generally affect total intakes of pellets, grass, or grass+pellets, animal performance on these various rations cannot be assumed to be similar until longer-term feeding studies have been performed, as reduced protein and energy concentrations in the pellets could significantly lower weight gains as level of leaf in the pellets increased.