The effect of dent versus flint maize genotype on site and the extent of starch and protein digestion, ruminal fermentation and microbial protein synthesis in the rumen of sheep
Year: 2005
Type: article
Abstract: Ruminal and whole tract digestibility of protein and starch, microbial protein yield in the rumen and molar proportions of volatile fatty acids (VFA) in the rumen fluid and faeces were determined in sheep that were given either maize silage derived from the dent (DTS) or flint type hybrid (FTS).Degradabilities in the rumen were determined by means of the in sacco method using three sheep and microbial protein yield in the rumen by means of urinary purine derivative excretion using four sheep.The extent of starch and protein degradation was significantly (P < 0.001) lower in FTS than in DTS (718 vs. 913 and 704 vs. 767 g•kg -1 respectively).Differences in whole tract starch and protein digestibility were small (986 vs. 997, P < 0.01 and 939 vs. 931 g•kg -1 , P < 0.05 in FTS and DTS respectively).The concentration of VFA in the rumen fluid was not affected by the type of silage (94.5 and 94.7 mmol•L -1 ); however, FTS induced a higher molar proportion of propionate (22.6% vs. 20.7%,P < 0.05) than DTS.The proportion of butyrate was higher in DTS (13.5% vs. 10.8%,P < 0.05).Microbial protein supply in FTS was significantly higher than in DTS (109.7 vs. 96.0g•kg -1 DM intake, P < 0.05).When expressed in relation to fermentable organic matter (FOM) intake, the differences between hybrids were greater (215.6 vs. 158.6g of microbial protein per kg FOM, P < 0.01).Lower efficiency of microbial protein synthesis in DTS was probably due to a lower pH value of rumen liquor (6.21 vs. 6.33,P < 0.05).FTS offered better conditions for the degradation of the fibre fraction in the rumen than DTS.The faeces of sheep that were given FTS contained less DM (304 vs. 371 g•kg -1 , P < 0.05) and tended to have a higher concentration of VFA (383 and 235 mmol•kg -1 DM, P < 0.1) indicating that in FTS at least one part of the starch which escaped digestion in the rumen passed through the small intestine undigested and was fermented in the large intestine.It was concluded that FTS could provide about three times more postruminally digested starch and about 20% more metabolisable protein than DTS. maize silage / starch digestion / protein digestion / microbial protein / sheep
Source: Animal Research
Authors: Jože Verbic, Drago Babnik, Vida Žnidaršic-Pongrac, Mojca Resnik, Ana Gregorcic, Veronika Kmecl
Institution: Agricultural institute of Slovenia
Language: English
Subfield: Animal Science and Zoology
Domain: Life Sciences
SDG: Zero hunger
Open Access status: bronze
OpenAlex ID: W2122560057