Silage preparation from tuna fish wastes and its nutritional evaluation in broilers
✍ Scribed by Vizcarra-Maga�a, Luis A; Avila, Ernesto; Sotelo, Angela
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 103 KB
- Volume
- 79
- Category
- Article
- ISSN
- 0022-5142
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✦ Synopsis
The present study was conducted to obtain tuna waste silage from the canning industry by using fresh ®sh viscera for the autolytic process. Chemical characterisation of the product and nutritional evaluation for broiler diets were then carried out. Three types of studies were performed. In study one the proximal composition was measured and three acid mixtures were tested for silage development. The formic±sulphuric acid mixture was chosen. The measurement of non-protein nitrogen (NPN) formation indicated that more than 50% NPN was obtained after 2 days of storage; pH changes were also measured and stabilisation occurred after 24 h. Contents of aerobic mesophiles, total coliforms, yeast and mould were reduced during the ®rst month of storage. Study two was then conducted to determine the proteolytic activity in fresh viscera, the changes in lipid oxidation and the trimethylamine formation during silage development. It was observed that cooked dark meat wastes were oxidised at the beginning, but trimethylamine did not change during 2 months of storage. Thirtynine per cent of tryptophan content was lost, but available lysine decreased only 8% from original content after 20 days of storage. Fe, Ca, P, Zn, Na and K contents were also measured. A larger batch of silage was obtained and dried after sorghum addition. The silage±sorghum ratio was 70:30. Four starter diets for 9-day-old broiler chicks were prepared at different levels from the ®nal dried silage (5, 10 and 15%). The control diet (0%) contained soybean meal as the predominant protein supplement. Food intake, weight gain and feed conversion were recorded during the short-time feeding study. There were no signi®cant effects of dietary inclusion on the ®nal dried product (p `0.05). The results showed that 15% of this product can be included without adverse effects on broilers.