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Adaptation and performance of feedlot lambs fed crude glycerin

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Author(s):
Márco Túlio Costa Almeida
Total Authors: 1
Document type: Doctoral Thesis
Press: Jaboticabal. 2018-03-19.
Institution: Universidade Estadual Paulista (Unesp). Faculdade de Ciências Agrárias e Veterinárias. Jaboticabal
Defense date:
Advisor: Jane Maria Bertocco Ezequiel; Eric Haydt Castello Branco van Cleef
Abstract

Crude glycerin has been used as a source of energy in ruminant diets, however, due to low capacity ruminal acidifying from products of their fermentation, it can be used to prevent ruminal metabolic problems. Two trials were conducted to evaluate the effects of crude glycerin (83% of glycerol) in diets of feedlot as ingredient able to reduces nutritional metabolic disorders in total or partial replacement of corn. In experiment 1, fifty-five 3-month-old crossbred lambs (Santa Inês × Dorper, 21.7 ± 2.7 kg bodyweight) were randomly allocated in individual pens indoors, assigned to a complete randomized block design and fed with four experimental diets, containing 0, 10, 20 or 30% crude glycerin. Three animals were slaughtered at the end of the pre-adaptation period (d0), twelve at the end of the adaptation period (d14), and the remaining (n= 40) when they reached ~35 kg BW. The feed intake, feeding behaviour, growth performance, carcass and meat traits, edible non-carcass components, stomach compartments and liver were evaluated. Regardless of the inclusion of crude glycerin, significant differences among feedlot periods were observed for the initial and final BW, shrunk final BW, ADG and DMI. The inclusion of more than 10% of crude glycerin in the diets increased days on feed and decreased DM intake and average daily gain. Crude glycerin increased number of chews and the time spent chewing per feed bolus. There were no effects of crude glycerin on pH and colour of Longissimus muscle at 45 min or 24 h after slaughter, as well as on other carcass and edible non-carcass characteristics. The addition of crude glycerin reduced perirenal fat without detrimental effect on others fat deposition sites. All stomach compartments, number of rumen papillae and mitotic index were higher for the finishing period. Crude glycerin treatments showed greater rumen weights when compared to control treatment in the finishing period. In the second trial, eight ruminally-cannulated male Santa Inês × Dorper sheep (64.5 ± 8.5 kg bodyweight) were distributed in a replicated 4 × 4 Latin square design. The ruminal parameters, such as pH, NH3-N and volatile fatty acids concentrations, in situ degradability, as well as in vitro greenhouse gas production and in vitro digestibility were evaluated. The experimental diets contained 0, 10, 20 or 30% of crude glycerin. The inclusion of crude glycerin in the diets tended to promote a quadratic effect in DMI, with greater values observed for treatments with 10 and 20% of crude glycerin. Crude glycerin tended to increase the ruminal pH and NH3-N, but linearly reduced the total molar concentration of VFA, acetic, butyric, isobutyric and isovaleric acids. The inclusion of crude glycerin in the diets linearly decreased the in vitro total gas and CO2 production (mL/g degraded) and tented to reduce CH4 (mL/g degraded). A linear increase of soluble fraction in water (“a”) of the diets were observed with the increasing inclusion of crude glycerin. The insoluble but potentially degradable fraction (“b”) of DM and NDF of the diets were linearly decreased and increased, respectively. The potential and effective ruminal degradation of the diets were markedly and linearly increased with the increasing inclusion of the by-product. Treatments linearly increased in vitro DM digestibility of diets and linearly reduced NDF digestibility. In conclusion, the increasing inclusion of up to 30% of crude glycerin in diets for crossbred lambs did not compromise the feed efficiency, stomach compartments and rumen papillae measurements in both periods of the feedlot. However, the inclusion of 10% of crude glycerin seems to be the most interesting strategy for the finishing period, promoting the greatest animal performance. The replacement of corn cracked grain by crude glycerin (up to 30% DM) changes rumen fermentation parameters, decreasing VFA production, in vitro total gas production and CH4. Additionally, the potential and effective degradation as well as in vitro DM digestibility of diets are improved while fiber digestibility is impaired. As no clinical manifestations resulted from ruminal acidosis (such as liver abscess, ruminitis, and lesions in the ruminal mucosa) were observed, we concluded that all diets were effective in the animals’ adaptation. (AU)

FAPESP's process: 15/04595-4 - Adaptation and performance of feedlot lambs fed crud glycerin
Grantee:Marco Túlio Costa Almeida
Support Opportunities: Scholarships in Brazil - Doctorate