Rafael Ginés

Effects of refrigeration, freezing-thawing and pasteurization on IgG goat colostrum preservation

The aim of this paper was to evaluate the effects of refrigeration, several different methods of thawing, and pasteurization on the concentration of IgG in goat colostrum. Three different experiments were designed to analyse these effects. In the first of these, 50 samples of goat colostrum were stored in a cold-storage room at a temperature of 4 ◦ C for a 3-month period. No statistically significant effects were observed within this time, although there was a reduction in IgG concentrations (32.98 and 25.11 mg/ml IgG at day 0 and 91, respectively). In the second experiment, 20 samples of goat colostrum were frozen and subsequently thawed using four different methods: hot water (60 ◦ C), refrigeration (4 ◦ C), room temperature (27 ◦ C) and microwave (55 ◦ C). The process was carried out seven times for each of the four methods. The method of thawing did not affect the colostrum IgG concentration. However, the repetition of freezing and thawing tended to reduce IgG concentrations, albeit to no significant degree (15.50 and 10.73 mg/ml IgG at cycle 0 and 7, respectively). In the third experiment, 30 goat colostrum samples were used and a reduction of approximately 35% of IgG concentration after pasteurization was observed. Refrigeration, freezing and pasteurization are suitable methods for conserving goat colostrum.

Starvation before slaughtering as a tool to keep freshness attributes in gilthead sea bream (Sparus aurata)

Instrumental quality parameters related to freshness were evaluated for gilthead sea bream (Sparus aurata) after different storage periods on ice (2, 4, 7 and 11 days of storage) for one, four and eight days of pre-slaughter starvation. The study was carried out on 360 gilthead sea bream from five different groups reared on a commercial fish farm. Starvation period had a significant effect on fish texture: the force necessary to compress 4 mm of flesh after two days ice storage in 1 day starved fish (16.50 ± 0.59 Newtons) was less than that for four day (18.98 ± 0.63 Newtons) and eight day starved fish (20.43 ± 1.12 Newtons). Significant differences in flesh puncture and flesh compression were not detected, although these values did increase with increasing starvation period. A significant increase in pH and myofibrilar protein solubility was also detected for fish starved for one day.

Prediction of kid carcass composition by use of joint dissection

Abstract Forty-seven Canary Caprine Group kids (6–15 kg body weight) were taken from the experimental flocks of Las Palmas de Gran Canarias University and the Canary Agronomic Science Institute and slaughtered. Their carcasses were halved and the left side was dissected into the major tissues. Linear regression analyses were used for predicting carcass tissue composition, using half carcass weight and joints tissue weights as independent variables. Taking account of the relative economic values of the joints, the most cost-effective predictor of carcass tissue composition was a combination of half carcass weight and shoulder dissection with an r 2 of 0.79, 0.81, 0.72 and 0.70 for muscle, bone, and subcutaneous and intermuscular carcass fat, respectively.

Comparative analysis of selected semi-persistent and emerging pollutants in wild-caught fish and aquaculture associated fish using Bogue (Boops boops) as sentinel species

The marine environment acts as a sink for diverse anthropogenic pollutants, although the environmental contamination may be non-uniformly distributed. In recent decades, the aquaculture sector has experienced a steady growth postulating as a good alternative for seafood production. However, a social debate exits about the differential level of pollutants in wild and farmed species. This study was designed to evaluate the level of pollutants in a sentinel species: Bogue (Boops boops) associated and non-associated to fish-farm cages. A total of 82 chemical substances were determined by gas chromatography-mass spectrometry, including persistent (polychlorobiphenyls (PCBs) and organochlorine pesticides (OCPs)), semi-persistent (bromodiphenyl ethers (BDEs) and polycyclic aromatic hydrocarbons (PAHs)), and emerging pollutants (such as organophosphate flame retardants (OPFRs) and UV-filters). In general, aquaculture-associated bogues showed lower levels of semi-persistent and emerging pollutants than wild-caught fish, especially when sums were considered. Thus, sum of BDEs was significantly lower in the aquaculture group (p=0.01). A similar trend was also observed for benzo(a)anthracene, the UV-filter 2-ethylhexyl-p-methoxycinnamate and some OPFRs. In the case of persistent pollutants, the sum of dioxin-like PCBs and sum of DDTs were lower in the group of wild-caught bogues (p=0.034 and p=0.003, respectively) than in aquaculture-associated bogues, as previously described for some aquaculture species. Fish feed appear as an important factor in the uptake of such substances suggesting a diet intervention to reduce their levels in the aquaculture products. Another interesting result is that for almost all chemical substances analyzed, bogues captured near sewage outfalls showed the highest levels of pollutants, pointing out the need of stringent measures for wastewater treatment units discharging in coastal areas. On the light of these results, further research in specific farmed and wild fish species in relation to their dietary value and pollutants levels seems to be mandatory.

Carcass Composition of Canary Caprine Group at Adult Age

Abstract Arguello, A., Fabelo, F., Capote, J., Gines, R., Afonso, J.M. and Lopez, J.L. 1999. Carcass composition of canary caprine group at adult age. J. Appl. Anim. Res., 15: 75–79. To study the carcass characteristics of mature goats from the Canary Caprine Group (CCG) 14 goats were slaughtered at adult age. The average live weight at slaughter was 57.88±2.44 kg, the hot carcass weight 25.33±1.52 kg and 2.17±0.33% chilling loss. The carcass yield amounted to 48.71±0.78%. The empty digestive tract, skin, udder and head contributed to over 75% of the total offals. In the left half of the carcass long leg accounted for 32%, shoulder 19%, ribs 23%, neck 9% and flank 17%. The carcass contained 61.79% muscle, 16.87% fat and 21.34% bone. Efforts have been made to predict certain parameters based on net live weight (live weight-digestive tract contents).

A Note on Yoghurt Utilisation in Artificial Rearing of Kids

Abstract Arguello, A., Gines, R. and Lopez, J.L. 1999. A note on yoghurt utilisation in artificial rearing of kids. J. Appl. Anim. Res., 15: 165–168. Eleven kids from the Canary Caprine Group were fed on a mixture of 50% commercial milk replacer and yoghurt. The growth rate was 91.3 g/d and the net carcass yield 48.70% with 6.22%, 26.97% and 60.12% fat, bone and muscles, respectively. The pH of muscles fell significantly in 24 h post-slaughter. Use of yoghurt in scarcity can be tried.