Nutritive value assessment of some Saudi Arabian foliages by Gas production technique in vitro

الملخص EN

Chemical composition, microbial rumen fermentation, energetic values and microbial mass of some Saudia Arabia foliages were investigated in comparison with alfalfa as high quality roughage using the Hohenheim gas test.

A gas test technique was performed using buffered rumen fluid collected from three rumen fistulated sheep.

Cumulative gas production was recorded at 3, 6, 9, 12, 24, 48, 72 and 96 h of incubation in vitro.

The investigated browses were Blue panic (Panicuma antidotale), Moringa oleifera, Jojoba (Simmondsia chinensis), Canary grass (Phalaris spp.) and Millet (Eleusine coracana) leaves.

The browses were collected at the wet season in Saudi Arabia.

Alfalfa and moringa leaves had the highest crude protein (CP) content, while the canary grass and blue panic had the lowest CP content.

The neutral detergent fiber (NDF), acid detergent fiber (ADF) and acid detergent lignin (ADL) were higher in blue panic, canary grass, millet and alfalfa, while the moringa leaves showed the lowest content of the fiber constituents.

The secondary compounds analyses showed negligible contents of these feeds for total phenol (TP), total tannins (TT) and condensed tannins (CT) except jojoba leaves.

Alfalfa, blue panic, moringa, canary grass and millet had negligible CT content, while jojoba leaves had the highest CT content (30.04 eq-g leucocyanidin kg-1DM).

The potential gas production was highest (p<0.05) for alfalfa, moringa, and millet leaves, while the canary grass and jojoba leaves recorded the lowest gas production.

Although, jojoba leaves produced less gas volume, it had the shortest lag time (L, 0.4139 h-1) and lowest rate of gas production (μ h-1).

The longest L value (2.379, h-1) was noted with canary grass.

There were significant (p<0.05) differences in terms of predicted short chain fatty acids (SCFA), metabolizable energy (ME), net energy (NE), organic matter digestibility (OMD) and microbial protein (MP).

The moringa and jojoba leaves in comparison with alfalfa showed the highest (p<0.05) SCFA, energy content, OMD and MP.

The ranking order of the investigated browse species on the basis of their energy content, organic matter degradability and microbial protein was moringa > jojoba > millet > blue panic > canary grass.

In conclusion, significant variations in in vitro fermentation and degradation were observed among different browse species collected from Saudi Arabia through the wet season.

The results suggest that moringa leaves are promising alternative feed resource and could be incorporated in ruminants feed mixtures to replace conventional roughage sources (alfalfa) without major problems.