Utilization of dietary carbohydrate in tinfoil barb (Barbonymus schwanenfeldii, Bleeker 1853) fry
An optimal inclusion of carbohydrates in aquafeeds exerts protein-sparing effect in many farmed fishes and improves their growth. Dietary starch facilitates pellet expansion during feed extrusion and enhances water stability of pellets due to binding capacity. Although freshwater omnivorous fish...
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| 格式: | Thesis |
| 语言: | English |
| 出版: |
2022
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| 主题: | |
| 在线阅读: | http://psasir.upm.edu.my/id/eprint/104560/1/FP%202022%2024%20IR.pdf |
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| 总结: | An optimal inclusion of carbohydrates in aquafeeds exerts protein-sparing effect in many
farmed fishes and improves their growth. Dietary starch facilitates pellet expansion
during feed extrusion and enhances water stability of pellets due to binding capacity.
Although freshwater omnivorous fish can better utilize carbohydrate, the efficiency
varies with species, and dietary carbohydrate level, source, type and physical form. The
present study was conducted to evaluate carbohydrate utilization ability of tinfoil barb
fry through five separate feeding trials. Tinfoil barb is an indigenous carp species that
has a great potential in aquaculture as a food and ornamental fish. All feeding trials were
conducted in 100 L aquaria fitted with top mechanical filters. Fry were stocked at 20 fish
per aquarium and fed to satiation twice a day for eight weeks. In the first trial, five
isonitrogenous and isocaloric diets with graded levels of corn starch (15, 20, 25, 30 and
35 %) were fed to the fish to determine its optimum starch utilization level. The diets for
subsequent feeding trials were prepared with selected native and pregelatinized starch
sources, sugars and α-cellulose to substitute corn starch. The fish fed 20% corn starch
exhibited highest (P<0.05) growth, and feed and protein efficiency. Third order
polynomial regression analysis revealed the maximum growth at 19.25% corn starch. At
this optimum level, native wheat, taro, tapioca, sago and corn starches had comparable
impact on fish growth. However, fish fed taro had lower (P<0.05) feed and protein
efficiency, and nutrient and energy retention than those fed corn. Dietary taro and wheat
groups had a lower (P<0.05) midgut α-amylase activity than those fed tapioca.
Compared to corn starch, dietary taro shrunk (P<0.05) the fish hepatocyte while wheat
shrunk its nucleus. Meanwhile, fish fed native and pregelatinized corn, sago and tapioca
starches exhibited similar growth, feed efficiency and nutrient retention despite
interactive influence of starch source and form (P<0.05) on feed digestibility and
physical properties. Among the different carbohydrate types, glucose caused poor
performance in fish (P<0.05) than sucrose, maltose, dextrin and tapioca starch. Growth
and midgut α-amylase activity of fish fed 19.25% dietary sucrose was higher (P<0.05)
than those fed glucose and tapioca starch. Nevertheless, survival of fish fed tapioca was
higher (P<0.05) after a 14-d challenge test with Aeromonas hydrophila than those fed
sucrose and dextrin. When the starch content of tinfoil barb diet was substituted with 0, 3, 6, 9 and 12 % α-cellulose, fish growth remained unchanged while α-amylase activity,
feed and protein efficiency and protein retention showed increasing trends with rising
fiber level. However, based on the overall fish performances, it was concluded that tinfoil
barb fry could better utilize native corn, sago and tapioca starches at 19.25% dietary
inclusion level. As corn starch is an imported commodity in Malaysia and locally
produced sago starch fetched high price, the use of native tapioca starch in tinfoil barb
diet was recommended. |
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