In Vitro Digestibility of Panicum maximum Hay Associated with Calliandra calothyrsus or Leucaena leucocephala in the Presence or Absence of Polyethylene Glycol (PEG)

The study of in vitro digestibility of Panicum maximum hay associated with Calliandra calothyrsus or Leucaena leucocephala in ruminants was conducted in May 2018 in the Animal Production and Nutrition Research Unit of the University of Dschang. Ruminal fluid (bovine), energy (Panicum maximum) and nitrogen sources (Calliandra calothyrsus or Leucaena leucocephala) with or without polyethylene glycol (PEG) were used in this study. At the beginning of the trial, sample of different rations based on Panicum maximum associated with 0; 30 and 50% of Calliandra calothyrsus or Leucaena leucocephala, in the presence or absence of polyethylene glycol was removed, dried and milled to determine the mineral, chemical composition and the evaluation of the in vitro digestibility. The results of this study showed that the addition of legumes increased the total nitrogen content (MAT) by 12.96, 16.67 and 17.05% DM, when Panicum maximum was associated with 0; 30 and 50% Calliandra calothyrsus and, (12.96; 13.77 and 14.03% DM) when Panicum maximum was associated with 0; 30 and 50% Leucaena leucocephala. The digestibility of organic matter (OM) (27.36; 36.02 and 33.59% DM), the content of digestible nitrogenous material (MAT) (10.49; 11.22 and 13.75 g / 100 g dOM), the feed unit milk (UFL) (0.74; 0.72 and 0.74 Kg DM) and the meat feed unit (UFV) (0.65; 0.74 and 0.71 Kg DM) also increased with the addition of Calliandra calothyrsus respectively in the proportions 0; 30 and 50% of the ration based on Panicum maximum hay. The parameters of in vitro digestibility evolved differently regardless of the level of incorporation of the different legumes into the diet. In fact, the in vitro digestibility parameters of Panicum maximum hay increased significantly (p<0.05) with the addition of legumes associated with PEG. The highest in vitro digestibility of organic matter (IVDOM) of the rations in the presence of PEG was obtained respectively with the rations P50C50 + PEG (50.38%) and P70L30 + PEG (51.49%) while, the lowest IVDOM was obtained with rations P70C30 + PEG (40.02%) and P70L30 + PEG (38.71) respectively. The highest gas (23.22 ml / 500 mg DM), volatile fatty acid (VFA) (0.50 mmol / 40 ml) and metabolizable energy (ME) (6.31 MJ / Kg DM) were obtained with the ration P50C50 + PEG. This study showed that adding legumes to Panicum hay maximizes nutrition and improves digestibility in ruminants.

Keywords: In vitro digestibility, Calliandra calothyrsus, Leucaena leucocephala, Panicum maximum, PEG.