Protein Sparing Effect of Sago Starch in Diet of Nile tilapia, Oreochromis niloticus (Linnaeus, 1758)

• Main Author: Benny Lawrence, Senawi
• Format: Thesis
• Language: English; English
• Published: Universiti Malaysia Sarawak (UNIMAS) 2020
• Subjects: SH Aquaculture. Fisheries. Angling
• Online Access: http://ir.unimas.my/id/eprint/36470/2/Benny%20Lawrence%20-%2024%20pgs.pdf; http://ir.unimas.my/id/eprint/36470/4/Benny%20Lawrence%20Anak%20Senawi%20ft.pdf; http://ir.unimas.my/id/eprint/36470/

Six isoenergetic (20.25±1.35 kJ/g) semi-purified experimental diets were formulated with three levels of protein, P(22%, 26% and 30% diet) and two levels of sago starch as source of carbohydrates, C(38% and 44% diet). A corn starch (C40%) diet was used as a control diet. Diets were fed to triplicate groups of tilapia (n=20), Oreochromis niloticus juveniles (mean weight 4.61 ± 0.04 g), to apparent satiation twice daily for 12 weeks. The results showed 100% survival rate for all diet groups in which fish fed on 38% sago starch diet incorporated with protein level, P22% (D1: 29.53 g), P26% (D2: 31.87 g) and P30% (D3: 32.32 g) were significantly higher (p < 0.05) on final body weight (FBW) than those fed on 44% diet treatments combined with P22% (D4: 23.29 g), P26% (D5: 25.65 g) and P30% (D6: 27.71 g). Whole body proximate compositions (n=6) were significantly (p < 0.05) affected by 38% and 44% of dietary sago starch with different level of protein, P22%, P26% and P30, respectively. Fish fed on 38% sago starch diets with protein level, P26% (D2: 13.64 mmol/L) and P30% (D3: 13.68 mmol/L) showed high significant different (p < 0.05) of glucose concentration in plasma (n=6) than those fish fed on diet treatments with protein level, P22%, P26% and P30% which contained 44% of sago starch. Significantly higher (p < 0.05) of triglyceride plasma (n=6) were observed in fish fed on 44% sago starch with protein level, P22% (D4: 6.52 mmol/L) compare with those fish from other diet treatments, meanwhile, total protein plasma (p < 0.05) were varied from 4.18 to 22.11 mmol/L. Nutrients digestibility (n=12) showed significantly (p < 0.05) high statistics on fish fed with ratio P30%:C38% (D3:80.12%), followed by P26%:C38% (D2:77.54%), P26%:C38% (D1:74.72%), P30%:C40% (D0:69.83%), P30%:C44% (D6:65.67%), P30%:C44% (D5:57.40%) and P30%:C44% (D4: 50.29%), respectively. Digestive enzyme activities (n=12) were significantly (p < 0.05) affected among all diets in which fish fed on treatment D3 with P30%:C38% ratio were statistically higher (amylase: 6.54 Umg-1, lipase: 5.68 Umg-1, protease: 0.77 Umg-1) compare with the other diet treatments. The carbohydrate metabolic enzyme activities (n=15) showed significant (p < 0.05) influenced between 38% and 44% sago starch incorporated with protein level, P22%, P26% and P30% recorded approximately from 0.76 to 0.97 Umg-1 (PFK), 0.73 to 0.96 Umg-1 (FBPase) and 0.78 to 0.95 Umg-1 (G6PD). Two-way ANOVA result confirmed that the interaction between different level of both protein and carbohydrate have significant (p < 0.05) influenced on growth performance, whole-body proximate compositions, blood plasma compositions, nutrient digestibility digestive enzyme and carbohydrate metabolic enzyme activities of O. niloticus juveniles. Overall, fish fed on 38% sago starch-based diets showed positive result and performed better than those fed with 44% diets. The study revealed the ability of O. niloticus juveniles to spare protein by dietary carbohydrate was at optimum level of 38% sago starch and 30% protein. Keywords: Sago starch, tilapia, growth, blood plasma, digestibility, digestive enzymes