IMIDA The team responds to the demands of the aquaculture sector in Murcia
Both oxidative processes such as microbial growth in fish could be delayed by the addition in the feed of natural preservatives
The length of fasting prior to slaughter of breeding golden, the use of vegetable ingredients in the manufacture of feed and the effect on the life of bream fed diets supplemented, extracts or essential oils of aromatic plants have been of a doctoral thesis, presented this week by Ana Alvarez Trujillo.
His study has been carried out in the Aquaculture Station of the Instituto Murciano Research and Agricultural Development and Food (IMIDA) under the Ministry of Agriculture and Water, is in San Javier.
IMIDA director, Adrian Martinez, noted that "the gold sold in Spain comes mostly from hatcheries."
Martinez added "aquaculture fish, unlike the extractive fishing, offers the advantage of occur under controlled conditions, so that, by knowing the influence of the factors of cultivation, it is possible to optimize the quality of final product" .
With this research, he concluded, "the team IMIDA Aquaculture answers some of the demands of this sector in Murcia raised in the Technology Transfer Conference to be held since 2006."
In aquaculture prior fasting is a common practice, in order to obtain a clean fish guts, no other food.
The time required to empty the digestive depends largely on temperature.
Taking into account seasonal variations in temperature in the Mediterranean, according to results obtained in the summer months within 24 hours of fasting would be sufficient, but in winter fasting should not be less than 40 hours.
The study of ice golden conservation subjected to different times of fasting revealed that the fasting time before slaughter significantly influences the lifetime, so that, at an average temperature of 20 ° C, a fast of more than 24 hours accelerates the deterioration of fish.
Thus, consider the tradeoff between the benefits of getting a free digestive remains of food and fasting-induced changes on the final product quality.
Vegetable ingredients
The second part of the thesis focused on the study of the effect of using a diet with 75 percent replacement of fish oil a mixture of rapeseed and soybean on the quality and life of the gold, given the increasing sector interest for the use of plant ingredients in feed manufacture.
The use of vegetable oils as part of the lipid source in the diet of golden modified fatty acid profile of meat, with some implications for the nutritional properties of fish.
Were also affected some quality parameters such as color and texture.
The partial substitution of fish oil by vegetable oils in the diet had no effect on the life of the gold stored in ice.
Despite noting signs of reduced lipid oxidation in the group of animals fed the diet with vegetable oil and some sensory and microbiological differences, there was no significant effect on the quality index or mesophilic counts, which are the that ultimately determine the acceptability of the product.
The third part of this thesis was to evaluate the effect on the life of golden fed diets supplemented extracts or essential oils from aromatic plants.
The results have shown that these compounds added to feed, may be greater or lesser extent, accumulated in fish muscle, so that their addition to the diet can have an added effect on fish quality, and delay deterioration.
We observed an antioxidant effect of diets supplemented with essential oil of thyme (Thymbra capitata), extract of rosemary (Rosmarinus officinalis) and an antibacterial effect of the diet with essential oil of thyme (Thymus zygisl).
Thus, both oxidative processes such as microbial growth in fish could be delayed by the addition in the feed of natural preservatives.
The thesis has been carried out in the Aquaculture Station IMIDA led by two researchers at the institute, Dr. Maria Dolores Hernandez Llorente and Dr. Benjamin Garcia Garcia.
He has been tutor of doctoral professor at the University of Murcia Javier Martinez Lopez.
The researcher Ana Alvarez Trujillo has enjoyed a predoctoral fellowship IMIDA under the Science and Technology Plan 2007-2010 of the Murcia Region, financed by the European Social Fund.
Different studies have been funded research projects of National Plans of National Advisory Board for Mariculture (Jacumar), the National Research Institute for Agriculture and Food Technology (INIA) and the Ministry of Agriculture and Water, funded by the FEDER funds.
Source: CARM