Fatty acid profile and in vitro rumen fermentation characteristics of maize silage augmented with canola silage

L A Mejía Uribe,F Hernández Ruipérez,I A Domínguez Vara,E Morales Almaráz,A A Rayas Amor

doi:10.4314/sajas.v51i2.9

L A Mejía Uribe, F Hernández Ruipérez + Show 3 more

Open Access

https://doi.org/10.4314/sajas.v51i2.9

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Abstract

The objective was to investigate the effect of replacing maize silage (MS) with canola silage (CS) on the chemical composition and fatty acid (FA) profile of total mixed rations (TMR) containing these silages, and on in vitro rumen fermentation and methane production from them. The canola (Brassica napus var. Monty) was cultivated on a small-scale agricultural farm and harvested at 148 days after sowing. Maize silage in a TMR was replaced with 0%, 15%, 25%, and 35% CS to make the rations CS0, CS15, CS25, and CS35, respectively. Proximate analyses of the rations were evaluated in a completely randomized design. The results showed that linolenic acid increased linearly with the level of CS, primarily at the expense of linoleic acid. In vitro dry matter digestibility (IVDMD) was similar among treatments. However, in vitro neutral detergent fibre digestibility (IVNDF) decreased linearly (P <0.05) when the CS proportion increased in the TMR. The lowest ammonia nitrogen content (P <0.05) was observed in CS35. The soluble fraction (A) increased (P <0.05) when the CS increased in the TMR from 0% to 35%. In vitro methane (CH4) production was lowest with CS25 and CS35, decreasing 34% and 23.9%, respectively, compared with CS0. Linolenic acid had a negative correlation with IVNDF (r = -0.94; P <0.05). The IVDMD and methane production were positively correlated (r = 0.60) (P <0.05). In conclusion, 25% and 35% augmentation of MS with CS in a TMR was an important source of linolenic acid (C18:3) and decreased in vitro methane production.

Highlights

Canola (Brassica napus) is a crop that shows drought resistance and uses soil water efficiently (SánchezGutiérrez et al, 2018)
Methane (CH4) gas was quantified according to the gas production technique (Theodorou et al, 1994) by measuring the accumulated CH4 concentration in the headspace of the bottles at 24 hours post incubation with an electrochemical methane sensor coupled to a portable analyser (Aeroqual Series 500®)
Each of these diets would satisfy the requirements for protein but would be slightly deficient in energy for the doe at this particular point in lactation

Summary

Introduction

Canola (Brassica napus) is a crop that shows drought resistance and uses soil water efficiently (SánchezGutiérrez et al, 2018). Brassica forage is nutritionally valuable for ruminants owing to its high metabolizable energy, crude protein contents, and low level of neutral detergent fibre (NDF) (Barry, 2013, Reta-Sánchez et al, 2015). Another advantage of using brassicas in diets for ruminant animals is that they increase the content of beneficial linolenic acid in milk compared with that produced when the animals are fed MS. The objective in this study was to investigate the effects on the chemical composition and FA profile of the diets of replacing MS with three levels of CS, and on in vitro ruminal fermentation and methane production of TMR

Material and methods

Results and Discussion

Conclusion