<i>Azolla</i> <i>pinnata</i>: Composition and Effect by Substitution of Cottonseed Cake on Growth Performance of Crossbred Piglets (Large White × Landrace) in Karusi, Burundi

The main objective of this study was to assess the nutritional composition of Azolla pinnata and evaluate its effect on growth performance in piglets when used as a partial substitute for cottonseed cake under practical farm conditions in Karusi, Burundi. A total of 16 weaned crossbred piglets (Large White × Landrace), aged two months, and were randomly allocated into four treatment groups. The piglets in the control group were fed with concentrate feed alone; piglets in Treatment 1 were supplemented with 3% Azolla, Treatment 2 with 6% Azolla supplement, and Treatment 3 with 9% Azolla. The trial was conducted for 45 days. Piglets were weighed at regular intervals of 3 days and the last 4 days throughout the 45-day experimental period. The analysis of crude protein (CP), fat (F), and crude fiber (CF) was conducted at the Laboratory for Soil and Agro-Food Products Analysis (LASPA) of ISABU while the analyses of moisture (M), dry matter (DM), organic matter (OM), and ash were carried out at the National Veterinary Laboratory (LNV) in Bujumbura. A one-way analysis of variance (ANOVA) was performed to test whether different levels of Azolla inclusion significantly influenced measured parameters such as weight gain, feed intake, and feed conversion ratio. A linear mixed-effects model was created. The nutrient compositions were Dry Matter 85%, Crude Protein 31.6%, fat 9.55%, CF 15.3%, Organic Matter 87.4, Moisture 15% and Ash 12.6%. The difference in feed intake between treatments was not statistically significant at the 5% level. The Average Daily Gain and FCR showed a significant difference (p Azolla supplement showed superior performance compared to the other treatments. Mixed-model analysis (random effect on piglet) showed that body weight increased significantly over time, with a clear effect from Day 22 onwards (p < 0.001). Treatment T3 resulted in a significant reduction in average body weight compared to the control (T0), while Treatment T2 showed a positive interaction with time, suggesting improved growth at certain days. No significant effect was observed for Treatment T1. No overall significant Day × Treatment interaction was detected.