Impact of brining and drying processes on the nutritive value of tambaqui fish (Colossoma macropomum)

Preservation of fish as diet ingredient is challenging in many tropical regions due to poor socioeconomic conditions and lack of freezing facilities. So, alternative preservation techniques could be viable to address the issue. The present study evaluated the effect of brine salting (15% w/v) prior to drying at different temperatures on the nutrient profiles of tambaqui fish (Colossoma macropomum). Whole fish samples (n = 48; 792 ± 16 g; 8 months old) were grouped into two as brine-salted and non-salted, and treated at seven different drying temperatures of 30, 35, 40, 45, 50, 55 and 60°C for a period of 23 h each. To evaluate the impact of Maillard reaction, reactive lysine was also quantified. Drying temperature had no effect on the evaluated macro- and micro-nutrients of tambaqui fish (P > 0.05) while brining reduced the overall protein concentration by 6% (58.8 to 55.4 g/100 g DM; P = 0.004). Brining significantly reduced many amino acids: taurine by 56% (7.1 to 3.1 g/kg; P < 0.001), methionine 17% (14.7 to 12.1 g/kg; P < 0.001), cysteine 11% (5.1 to 4.4 g/kg, P = 0.016), and reactive lysine 11% (52.0 to 46.4 g/kg; P = 0.004). However, alanine, arginine, and serine were not affected by brining (P > 0.05). Brining also reduced the concentrations of Se by 14% (149 to 128 μg/kg DM; P = 0.020), iodine 38% (604 to 373 μg/kg DM; P = 0.020), K 42% (9.71 to 5.61 g/kg DM; P < 0.001) and Mg 18% (1.32 to 1.10 g/kg DM; P = < 0.001) versus an anticipated vast increase in Na by 744% (2.70 to 22.90 g/kg DM; P < 0.001) and ash 28% (12.4 to 16.0 g/100g DM; P < 0.001) concentration. Neither brining nor drying temperature induced changes in % lysine reactivity and fat content of tambaqui fish (P > 0.05). Agreeably, results of multivariate analysis showed a negative association between brining, Na, and ash on one side of the component and most other nutrients on the other component. In conclusion, drying without brining may better preserve the nutritive value of tambaqui fish. However, as a practical remark to the industry sector, it is recommended that the final product may further evaluated for any pathogen of economic or public health importance.

Exploring the functional and metabolic effects of adding garra fish meal to a plant-based broiler chicken diet

The present study evaluated the metabolic and functional effects of adding garra meal to a broiler chicken diet. 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 formulated starter and grower basal diets. The experiment lasted for 42 days. Feed intake and body weight gain increased at the starter and grower phases of broilers with garra meal addition (P < 0.05). Broiler chickens fed 30% garra meal were more efficient in converting feed to body weight and yielded the highest carcass weight (P < 0.05). Crude protein ileal digestibility coefficient was higher with 20% (76.2%), and crude fat with 20 (92.1) and 30% (92.6%) garra meal receiving groups (P < 0.05). The increase in individual and total esterified carnitine concentrations in dried blood spots demonstrated the elevated metabolic rate with 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) without any apparent effect on ketogenesis in terms of serum 3-hydroxybutyrylcarnitine to acetylcarnitine ratio. Yet, it likely showed that part of the amino acids from garra meal were used as glucogenic substrate (P < 0.05). Histomorphometry data showed 20% garra meal addition elevated villus height, crypt depth and their ratio in the proximal parts of the small intestine (duodenum and jejunum) with the opposite results observed in the more distal part (ileum) with the highest for the control group (P < 0.05). It can be concluded that garra meal 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, absorption and nutrient metabolism.