Effect of Azolla pinnata inclusion in corn silage on digestibility, ruminal fermentation, blood parameters and growth performance of Barki male lambs

Azolla (Azolla pinnata- Ap) is a novel and unconventional source of animal feed, which enhances the nutritional value and reduces feeding costs. Azolla has not been used in animal feeding as silage before, so the aim of this study was to investigate the impact of increasing levels of Azolla as a partial component in corn silage on the nutrient digestibility, rumen fermentation, blood parameters, and growth performance of Barki male lambs. In ensilage processes, different levels of wilted Azolla were mixed in chopped corn plants (without cobs) in four treatments, as follows: (1) 100% chopped corn without Azolla; (2) 95% chopped corn plus 5% Azolla; (3) 90% chopped corn plus 10% Azolla; (4) 85% chopped corn plus 15% Azolla. A growth trial was conducted using twenty-eight healthy Barki male lambs (8 months old, average initial body weight of 31.25 ± 0.60 kg), which were divided into four groups (n = 7). Lambs in each group were fed one of the four types of silage produced as a single diet at 3% dry matter of body weight. Results revealed that the inclusion of Azolla in corn silage significantly (P˂0.05) increased crude protein content and enhanced physical and fermentation characteristics. All nutrients digestibility were improved in corn silage mixed with different levels of Azolla compared to corn silage (P˂0.05). The concentrations of ammonia and total volatile fatty acid in the rumen reached their highest values at 3 h post-feeding. They were significantly higher (P = 0.004 and P = 0.045, respectively) for lamb groups fed any of three varieties of Azolla-corn silage than lambs fed corn silage. The highest (P˂0.05) values of body weight at 60 and 90 day, total body gain and average daily gain were recorded in lambs fed silage contained 15% Azolla, followed by those fed silage contained 10% and 5% Azolla, while the lowest values were recorded in lambs fed control silage. Lambs fed silage contained 10% and 10% Azolla had the greatest total protein and albumin values (P = 0.027 and P = 0.021, respectively), followed by lambs fed silage contained 5% Azolla, while those fed corn silage had the lowest values. In conclusion, the physical, chemical and fermentation characteristics of silage of Azolla corn mixture were enhanced. They can be used successfully in Barki male lamb rations, with beneficial effects on digestibility, nutritive value, rumen fermentation and growth performance.