Welcome to Acta Prataculturae Sinica ! Today is Share:

Acta Prataculturae Sinica ›› 2021, Vol. 30 ›› Issue (9): 159-167.DOI: 10.11686/cyxb2020320

Previous Articles    

Effects of different doses of sodium nitrate on fatty acid composition and microbial population in in vitro simulation of buffalo rumen fermentation with added linoleic acid

Yan-xia GUO(), Meng-wei LI, Zhen-hua TANG, Li-juan PENG, Kai-ping PENG, Fang XIE, Hua-de XIE, Cheng-jian YANG()   

  1. Key Laboratory of Buffalo Genetics,Breeding and Reproduction Technology,Ministry of Agriculture and Guangxi,Buffalo Research Institute,Chinese Academy of Agricultural Sciences,Nanning 530001,China
  • Received:2020-07-07 Revised:2020-09-27 Online:2021-08-30 Published:2021-08-30
  • Contact: Cheng-jian YANG

Abstract:

This research explored the effects of different doses of sodium nitrate on the composition of fatty acids and the numbers of microorganisms in in vitro simulation of buffalo rumen fermentation with added linoleic acid. Three female buffaloes with permanent rumen fistula were used. The ratio of dietary concentrate to roughage was 40∶60. The experiment comprised five replicates of four experimental treatments: a blank control (CK) and addition of sodium nitrate at rates of 1, 2 or 3 mg·mL-1, with 0.25 mg·mL-1 linoleic acid added in each case. Gas and methane production were measured after 3, 6, 9, 12 and 24 h anaerobic incubation in vitro, and the fermentation parameters, fatty acid concentrations and numbers of rumen microorganisms were determined after 24 h incubation. It was found that adding sodium nitrate significantly reduced the total gas production and methane production (P<0.05). Adding sodium nitrate also significantly increased the simulated rumen pH value and ammonia nitrogen (NH3-N) concentration (P<0.05), significantly reduced the contents of isobutyrate and isovaleriate (P<0.05), but had no significant effects on the concentrations of total volatile fatty acids (TVFA) (P>0.05). With the addition of 1 mg·mL-1 sodium nitrate, the contents of C18:2cis-9, trans-11, C18:2trans-10, cis-12 and unsaturated/saturated fatty acid ratios were significantly higher than those in other groups (P<0.05). The concentration of C20:5n3 (eicosapentaenoic acid) in the 1 mg·mL-1 sodium nitrate group was significantly higher than that in the 3 mg·mL-1 sodium nitrate group (P<0.05), and the concentration of C22:6n3 (docosahexaenoic acid) with 2 mg·mL-1 sodium nitrate added was significantly higher than that of other groups (P<0.05). The number of protozoa in treatments with added sodium nitrate was significantly lower than for CK (P<0.05). The number of methanogens in treatments with 2 and 3 mg·mL-1 added sodium nitrate was significantly lower than in the 1 mg·mL-1 sodium nitrate treatment (P<0.05), and the numbers of bacteria, fungi, Butyrivibrio fibrisolvensButyrivibrio proteoclasticusAtypical butyrivibrio, and Butyrivibrio hungatei in the 1 mg·mL-1 sodium nitrate treatment were significantly higher than in other treatments (P<0.05). In summary, the addition of 1-3 mg·mL-1 sodium nitrate and 0.25 mg·mL-1 linoleic acid in vitro significantly reduced methane generation while maintaining the TVFA concentration. Moreover, 1 mg·mL-1 sodium nitrate promoted the formation of conjugated linoleic acid (CLA), optimized fatty acid composition, and increased the numbers of most rumen microorganisms.

Key words: sodium nitrate, in vitro fermentation, methane, biohydrogenation, rumen microorganism