Exploring the Functional and Metabolic Effects of Feeding Garra Fish Meal to Broiler Chickens
The present study evaluated the metabolic and functional effects, beyond nutritive value, of feeding garra meal to broiler chickens. Three hundred twenty Sasso-breed day-old chicks were randomly assigned to four dietary treatments with either 0, 10, 20 or 30% garra meal added on top of a formulated starter and grower basal diets. The experiment lasted for 42 days. There was a gradual increase in feed intake and body weight gain with increasing garra meal addition (p < 0.05). Broiler chickens
... 30% garra meal were more efficient in converting feed to body weight and yielded the highest carcass weight (p < 0.05). Crude protein and crude fat digestibility coefficients were higher with the garra meal receiving groups with the highest values (74.8 ± 1.6 and 92.3 ± 0.6) recorded with 20% and 30% garra meal additions, respectively (p < 0.05). The increase in individual and total esterified carnitine concentrations in dried blood spots demonstrated the elevated metabolic rate with increasing garra meal addition (p < 0.05). A better supply of glucogenic substrate to the citric acid cycle was seen with garra meal addition due to the increase of propionylcarnitine to acetylcarnitine ratio (p < 0.05) while no effect was observed on ketogenesis as measured through the 3-hydroxybutyrylcarnitine to acetylcarnitine ratio (p > 0.05). Yet, it likely showed that part of the higher amino acids (Leucine, Methionine and Citrulline) uptake due to garra meal was used as glucogenic substrate (p < 0.05). Histo-morphology showed gradual increases in villus height, crypt depth and their ratio in the proximal parts of the intestine (duodenum and jejunum) with the opposite results observed in the more distal part (ileum) with garra meal addition (p < 0.05). It can be concluded that garra meal strongly improved broiler performance when added to a plant-based diet and only few parameters warranted for caution when using more up to 30% garra meal addition. Beyond growth performance, garra meal generated a shift to a more efficient digestion and nutrient metabolism, and induced changes in edible muscle that may aid in solving shortages in the Ethiopian human diet.