Physiological and Productive Impacts of Including Artificial Saliva in Lamb Diets: Growth, Carcass Traits, and...

The intensive lamb rearing and finishing systems are usually based on nutritionally balanced concentrate-based rations. However, the inclusion of feed additives is often necessary to avoid possible disturbances of digestibility. Artificial saliva plays an important role in ruminal buffering, improving the digestibility of the feed under conditions where natural saliva production may be insufficient. The study aimed to evaluate the effects of dietary artificial saliva (AS) on the total mixed ration (TMR) on lambs' growth performance, carcass characteristics and the efficacy of ruminal fermentation. Forty-five male Naemi lambs (mean body weight of 23 ± 1.8 kg) were randomly assigned to five experimental groups (n = 9 per group) and kept in complete confinement with water and adlibitum feeding. During the 84-day feeding period, animals received isonitrogenous and isoenergetic TMRs that vary in AS inclusion by level: T0 (0% AS), T2 (1.5% AS), T3 (3.0% AS), T4 (4.5% AS), and T5 (6% AS). No significant differences (p > 0.05) were observed in the overall performance parameters. However, lambs fed the control diet (0% AS) had a higher body weight (BW), average daily gain (ADG), and feed intake (FI) than those receiving AS supplementation (p < 0.01). Ruminal pH measured 3 h after feeding and at slaughter remained comparatively stable in lambs fed 3% and 4.5% AS treatments, whereas it declined to 5.21 in the control group. Dietary inclusion of AS at 4.5% significantly increased (p < 0.05 < 0.05) the molar proportions of butyric acid, iso-valeric acid, and valeric acid in ruminal fluid while other levels of artificial saliva were associated with reduced concentrations of volatile fatty acids (VFAs). In conclusion, AS effectively functioned as a buffering agent, enhancing dietary safety without adverse health effects.