117,427 research outputs found
Pig production systems and related effects on pre-slaughter animal welfare and meat quality
No full textPreslaughter handling practices, such as fasting, transport, mixing and human interventions affect the welfare of pigs and carcass and meat quality individually and cumulatively. Behavioral and physiological studies conducted during the preslaughter period revealed that producer-controlled factors at the farm, such as housing system, previous handling experience, genetics, gender, nutrition and slaughter weight can have an impact on pigs’ ease of handling and sensitivity to stress, which result in loss of profits for the pork chain due to transport losses, reduced carcass value due to lesions and bruises and meat quality defects. Research has shown that pigs originating from enriched housing conditions, not over-selected for lean deposition and trained to be handled are easier to handle and more resilient to the effects of physical stress prior to slaughter. However, the effects on meat quality are not clear. The production of entire males and immunocastrates can be a valid alternative to surgical castration, provided specific practices are applied to limit aggressiveness in mixed group situations and the risk of bruised carcasses. Recommendations for the transport and handling of heavier slaughter pigs must be adapted to improve ease of handling and reduce transport losses, aggressiveness and fatigue-related meat quality defects. The response of pigs to preslaughter physical stress and feed deprivation can be affected by ractopamine dietary supplementation, feed composition and feeding regime. The objective of this paper is to overview the effects of on-farm producer-controlled factors on pigs’ response to preslaughter handling and meat quality, and environmental, social and economical sustainability
Road Transport: A Review of Its Effects on the Welfare of Piglets
No full textThe purpose of this review is to present the best available scientific knowledge on key effects of pre-transport and transport factors influencing the response of piglets to transport stress and post-transport recovery. To date, research on piglet transportation particularly focused on the effects of season (i.e., heat and cold stress), vehicle design features (ventilation type and deck/compartment location), space allowance and transport duration, and piglet genetics. More specifically, in this review the effect of transport duration has been dealt with through its impact on death rate, behaviour and physiological response, and feeling of hunger and thirst. Based on the available literature, clear conclusions can be drawn on the vulnerability of piglets to heat stress during transport. Both short and long transportation have an effect on piglet welfare, with effects being biased by the genetic background, ambient conditions and vehicle design. Further studies investigating the impact of factors such as vehicle design, truck stocking density and environment, piglet genetic background, and weaning age are needed
Radiation-induced free radical reactions in polymer/drug systems for controlled release: an EPR investigation
No full textThe primary and secondary free radical intermediates in the gamma radiolysis of poly(D,L-lactide-co-glycolide) (PLGA) and clonazepam loaded PLGA microspheres were investigated by matrix EPR spectroscopy in the temperature range 77-298K. Drug-polymer interactions were found to be important leading to significant deviations of the G(radicals) from the additivity law. In particular, in the mixed system a stabilization of the polymer matrix with respect to the radiation damage was detected, witnessed by a decrease of the overall polymer radicals yield which is accompanied by an increase of the drug radicals yield. These effects have been attributed to the scavenging properties of the nitro group with respect to electrons and polymer radicals. It is conceivable that such conclusions be of general application for all pharmaceutical formulations containing drugs bearing nitro groups in their chemical structure
Which genes are best indicators for lesion age determination on the pig carcass? A preliminary study.
No full textAssessing the age of lesions on the carcass may help determine the time of their infliction and identify the causes. This study aimed at identifying which genes are the best indicators of lesion age on the pig carcass. Five identical lesions were inflicted at the same time on the shoulders of 10 pigs (100± 20 kg) using a piglet’s lower jaw. Five biopsies on each pig were performed at 1, 4, 8, 24 and 48h after injury (1 biopsy per lesion). Intact skin was the control. Local anaesthetic and analgesics were used to reduce pain. To assess the effect of slaughter and carcass treatment on gene expression, 5 of the 10 pigs were slaughtered 24h after the infliction of two lesions in the hams. Biopsies were taken before and after slaughter (BS and AS, respectively), and after carcass singeing. The qPCR method was used to quantify the expression of 98 genes involved in wound healing, using the 2^(-CT) method. Since carcass handling induced a degradation of the RNA, only samples taken before carcass dehairing were used. Genes that were not differently expressed between BS and AS were first tested on 5 pigs in all lesion age categories. Fourteen selected genes were then tested on all pigs. Statistical analyses were performed using the PROCMIXED procedure of SAS. Eight genes (CCL2, COX2, IL2, IL6, IL8, MMP1, SERPINE1, TIMP1) presented different expression patterns by the age of the lesion (P<0.05). In particular, COX2 appears to be a useful indicator of lesions of 1h (1h=6.2 [3.2-12.1], 4h=1.4 [0.7-2.6], 8h=1.7 [0.9-3.4], 24h=1.6 [0.8-3.1], 48h=1.1 [0.6-2.2]; P<0.01), and MMP1 of 4-8h (1h=1.9 [0.7-5.5], 4h=35.6 [12.4-102.3],8h=19.2 [6.7-55.3], 24h=4.0 [1.4-11.4], 48h=1.3 [0.4-3.6]; P<0.001). Based on their different expression by age of lesion, the identified genes may be used in larger-scale studies to validate on-field methods for this assessment
SPIN LABELLING OF DEGRADED POLYPROPYLENE. PART 1. FORMATION OF OXAZOLIDINE NITROXIDE
No full textAbstract: The kinetics of nitroxide formation on a polypropylene (PP) chain by reaction between carbonyl groups of gamma-irradiated PP and 2-amino-2-methyl-1-propanol has been studied, During the reaction the total concentration of carbonyl and amine groups passes through a maximum. At the end of the reaction a weak ESR signal due to nitroxide groups was detected and its intensity was strongly enhanced by peroxidation with m-chloroperbenzoic acid. The presence of nitroxides after the reaction with the aminoalcohol has been explained by the interaction of an oxazolidine moiety with singlet oxygen coming from the decomposition of PP-hydroperoxides or by reaction of the latter compounds with the oxazolidine nucleus
ESR molecular dynamics study at the oxidation sites of polypropylene with nitroxyl spin labels and spin probes
No full textSpin Labelling at Oxidation Sites in Polymers
No full textThe selective spin labelling of polypropylene films for monitoring the molecular dynamics at the oxidation sites has been obtained by reacting 3-chloroformyl-2,2,5,5-tetramethylpyrroline-1-oxy1 with the OH groups formed in the photo oxidation. The line shape changes of the ESR spectrum of the spin label, detected as a function of the temperature, have been interpreted in terms of a very anisotropic motion with fast rotation about a molecular axis oriented approximately along the N-O bond; also evidence of the presence of two different populations of nitroxides with different mobilities has been obtained. The use of sulphonyl radicals as novel probes for molecular motion in polymers has also been tested
The role of silica in radiation induced grafting and crosslinking of silica/elastomer blends
No full textWhen silica/polybutadiene and silica/styrene-butadiene are submitted to g irradiation at 77 K a scavenging
of the silica radiolytic species by absorbed vinyl units takes place at the surface with concomitant
grafting and crosslinking of the polymers. Key intermediate in such reactions are SiO2-bonded radicals of
structure SiO2eC(CH3)CH(R)(R0). The role of silica is rationalized in terms of the following steps: a)
absorption of the radiation energy in the bulk of the silica particles followed by exciton migration at the
surface; b) reactions of excited groups (silanols) with absorbed vinyl units giving SiO2-bonded radicals; c)
crosslinking of the polymers initiated by grafted radicals
Fundamentals of animal welfare in meat animals and consumer attitudes to animal welfare
No full textThe science of animal welfare has made significant advances in understanding the feelings of animals in production and proposing a variety of novel practices to create a fair balance between animal needs, production costs, and consumers' requirements. Nowadays, consumers base their buying decisions on their personal perceptions of value, resulting from a balance between price and quality and differences in social, cultural, and educational status. The lack of knowledge about livestock production practices and their impact on animal welfare and meat quality also explains the poor consciousness in large part of meat consumers worldwide. The numerous initiatives of the food supply chain in response to the consumer requirements for improved animal welfare are having the most visible influence on their purchase behavior. However, they are also creating them some confusion due to lack of transparency and completeness of information through specific product labeling at the retail level
Photoxidation and Stabilization of Polymers
No full textA general description is presented of polymer photo-oxidative degradation and of the state of the art photostabilization of some polymer classes. The polymers discussed include polyvinyl chloride, polyamides, elastomers, polystyrene and the polyolefins, polyethylene and polypropylene. A number of challenges remain open to study, the more important of which are listed
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