Evaluation of the Feed Nutritional Value of Noni (Morinda citrifolia) Meal for Holstein Dairy Cows

Simple Summary Three follow-up experiments as one set were conducted to evaluate the feed nutritional value of noni (Morinda citrifolia) meal to be included in the diet of Holstein dairy cows. An in vitro study was conducted to explore the effect of noni meal on rumen fermentation characteristics. An in situ study was conducted to evaluate the rumen degradation characteristics of noni meal, using wheat bran as a control. Finally, an in vivo study was carried out to investigate the applicability of noni meal as a feed ingredient for Holstein dairy cows. The in vitro study showed that the addition of noni meal up to 7% at 24 and 48 h of incubation did not negatively affect rumen fermentation characteristics. The in situ study showed that the rumen degradable protein content of the noni meal was high. The in vivo study showed that 1.5% noni meal can be used as a feed ingredient for Holstein dairy cows to improve the C18:1 fatty acid concentration in the milk. In three consecutive studies, we evaluated the effects of noni (Morinda citrifolia) meal on rumen fermentation and degradation characteristics, production performance, physiological parameters, and milk fatty acid profile in Holstein dairy cows. In in vitro (first study) and in situ (second study) experiments, rumen fluids from two fistulated Holstein dairy cows were used. The concentration of noni meal added was 0 (control), 1, 3, 5, or 7% of the basal diet (DM basis). In the in situ experiment, wheat bran was used as a control. Triplicated bags were incubated for 0, 4, 8, 12, 24, 48, 72, or 96 h. In an in vivo experiment (third study), 38 Holstein cows (145 +/- 87 days DIM; 1.8 +/- 0.9 parity; 35.4 +/- 6.3 kg/day milk yield) were equally assigned to the control and treatment groups (19 cows each). Basal feed and noni meal pellets (1.5% of total feed DM basis) were fed to the treatment group. The control group was also fed the basal feed and pellets containing 0% noni meal. There were no significant differences in in vitro dry matter digestibility, pH, total gas production (TGP), CH4, NH3-N, and volatile fatty acids (p > 0.05). In the in situ experiments, the crude protein (CP) rapidly soluble fraction 'a' (CP-a) was higher in noni meal than in wheat bran, and rumen degradable protein was also higher in noni meal than in wheat bran. In the in vivo experiments, when noni meal pellets were fed, there was no significant difference in milk yield and composition, but the triglyceride levels decreased (p < 0.05), the C18:1 fatty acid level increased (p < 0.05), and the C18:0 fatty acid level decreased (p < 0.05). Collectively, noni meal can be used as a feed ingredient up to 1.5% (total feed DM basis) in Holstein dairy cows and as feed supplementation to increase the C18:1 fatty acid level in milk.