Comparison of bacterial pellets and microbial markers for the estimation of the microbial nitrogen and amino acids flows from single flow continuous culture fermenters fed diets containing two‐stage olive cake

Abstract

The effects of using effluent bacteria (EB) and solid- (SAB) and liquid- (LAB) associated bacteria and diaminopimelic acid (DAPA) or purine bases (PB) and partially substituting alfalfa hay (AH) by a concentrate including olive cake on the microbial N flow (MNF) and amino acids (AA) flow were investigated with continuous culture fermenters fed AH and a mixture of AH and a concentrate containing barley grains and two-stage olive cake (2:1 ratio) without (AHCO) or with polyethylene glycol (PEG) (AHCOP). The MNF was not different among diets with SAB or LAB (p = 0.302 and 0.203, respectively) and DAPA, but differed with PB (p = 0.021 and 0.014, respectively). With EB both markers detected similar differences, AHCOP showing a higher value (p < 0.05) than AH and AHCO. The MNF was higher (p < 0.001) with PB than DAPA. Daily flow of non-essential AA was not different (p = 0.356) among diets but essential AA flow was higher (p < 0.05) for AH and AHCOP than for AHCO. The SAB presented lower (p < 0.05) total AA than LAB and higher total AA (p < 0.05) for diet AH than AHCO. The AA profile of EB was similar to that of LAB, but alanine and leucine were higher (p < 0.05) in EB than in LAB. Microbial contribution to AA flow was 45.4%, 55.6% and 58.1% for diets AH, AHCO and AHCOP respectively. With both markers, microbial AA flow was higher (p < 0.05) for diet AHCOP compared with AH (451 and 355 mg/day, respectively), but not different (p > 0.05) for AHCOP and AHCO (389 mg/day). The results would indicate that olive cake could be used in the practical feeding of small ruminants without negatively affecting microbial AA N supply.

Effect of maize silage to grass silage ratio and feed particle size on protein synthesis and amino acid profile in different microbial fractions in a semi-continuous rumen simulation

“…Changes in the availability of nutrients, as described between treatments F and C (Hildebrand et al, 2010), did not affect N contents of the microbial fractions. In accordance with Molina-Alcaide et al (2009) interactions between microbial fraction and diet on AA profile could be detected in this study. It is supposable that SAM in C treatments had easier access to the 15 N pool of the liquid phase because of lower bulk density, and consequently, a better flushing of feedbags compared to F treatments.…”

Comparison of microbial fermentation of high- and low-forage diets in Rusitec, single-flow continuous-culture fermenters and sheep rumen

“…Efficiency of microbial growth values was in the range of those previously reported for similar diets in SFCCF (Meng et al, 1999;Molina-Alcaide et al, 2008) and Rusitec fermenters (Blanchart et al, 1989;Gó mez et al, 2005;Giraldo et al, 2007). Rumen microbial yield and efficiency of microbial growth depend on microbial growth rate and maintenance requirements (Hespell and Bryant, 1979), both varying with bacterial species and environmental conditions, such as diet, pH, dilution rate and solids retention time (Stern and Hoover, 1979;Meng et al, 1999;Dewhurst et al, 2000).…”

Ruminal fermentation, microbial growth and amino acid flow in single-flow continuous culture fermenters fed a diet containing olive leaves

“…The values of microbial growth efficiency ranged from 15.3 to 20.8 mg microbial N/g digested carbohydrate and were in the range of those previously obtained in fermenters fed diets based on AH or OL supplemented with different concentrates (Martín‐García et al., 2006; Molina‐Alcaide et al., 2008; Moumen et al., 2008). Rumen microbial yield and its efficiency depend on microbes growth rate and maintenance requirements, both varying with microbial species and environmental conditions, such as diet, pH, dilution rate and solids retention time (Dewhurst et al., 2000).…”