Impact of Peas ( Pisum Sativum L.) as a Sustainable Source of Protein in Growing Pigs’ Diets on Production Efficiency, Nitrogen Metabolism and Gastrointestinal Tract Health

This pilot study evaluated the effects of dietary pea inclusion as a sustainable and nutritional alternative protein source on growth performance, nitrogen balance, digestibility, and intestinal health on nine castrated male Topigs hybrid pigs (three pigs/group), with an initial average weight of 20 ± 2.5 kg, for 45 experimental days. To conduct this digestibility pilot study, the pigs were kept individually in metabolic cages. Three experimental groups were compared: T 0 (control), T 10 (10% pea inclusion), and T 20 (20% pea inclusion). Growth performance parameters, such as the feed conversion ratio (FCR), daily feed intake (DFI), and dry matter intake (DMI), were significantly higher in the T 10 and T 20 groups compared to T 0 ( p < 0.05). Nitrogen retention was significantly higher in the T 10 group ( p = 0.042) compared to the T 0 group only. Biochemical markers, such as the total bilirubin (T-Bil) and uric acid (UA) levels, were significantly higher in T 20 compared to T 0 ( p < 0.05). The short-chain fatty acids (SCFAs) increased significantly in the ceca and ilea of the T 10 and T 20 groups compared to T 0 , with higher levels of acetic acid (C2) and butyric acid (C4). A positive effect on Lactobacillus populations was observed in both the ileum and cecum in the T 10 and T 20 groups ( p < 0.05). Intestinal morphology analysis revealed that the villus width, villus area, and crypt depth were significantly increased in the jejuna and ilea of both pea-fed groups. The N retention, SCFA concentration, and Lactobacillus population from the ileal and cecal segments showed a strong correlation. These findings suggest that the dietary inclusion of peas positively impacts growth performance, nitrogen retention, and intestinal health, with enhanced microbial populations and improved gut morphology.