Application of Enzyme Digestion and Deconjugation Followed by Quick, Easy, Cheap, Effective, Rugged, Safe Extraction and Liquid Chromatography-Tandem Mass Spectrometry Methodology To Determine Ractopamine Residue in Pork.

A new methodology is proposed for ractopamine residue analysis in pork. It consists of enzyme-mediated digestion and deconjugation steps; modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) extraction; and liquid chromatography-tandem mass spectrometry (LC-MS/MS). In brief, the samples were digested with protease and then deconjugated with ß-glucuronidase enzyme; they were then subjected to extraction and cleanup by QuEChERS and underwent sequential analysis by LC-MS/MS. The method performance was evaluated in accordance to the validation guidelines regulated by the Brazilian Ministry of Agriculture and Food Supply. The limit of detection was 0.15 µg/kg and limit of quantification was 0.5 µg/kg. When the method was applied to real samples, ractopamine residue was found in concentrations (up to 7.86 µg/kg) below international recommendation limits up to 10 µg/kg. The method is sensitive, accurate, quick, simple, and suitable for routine analysis; therefore, it is a monitoring tool that may be adopted by laboratories to achieve compliance levels.

Evaluation of brain damage resulting from penetrating and non-penetrating stunning in Nelore Cattle using pneumatically powered captive bolt guns.

Brain damage resulting from penetrating and non-penetrating stunning of Nelore cattle using pneumatically powered captive bolt guns was evaluated. Heads were shot using penetrating captive bolt gun with 160 psi (P1; n = 10), 175 psi (P2; n = 10), 190 psi (P3; n = 12), and non-penetrating operating with 220 psi (NP; n = 10). Skin and bone thickness, bolt penetration angle, bolt penetration depth, haemorrhage over the cerebral hemispheres and laceration were assessed. Only P1 had shots that failed to perforate the skull (n = 2; 20%). Bolt penetration depth and haemorrhage over the right cerebral hemisphere was significantly (P ≤ 0.05) greater for P3. Subarachnoid haemorrhage over the frontal, parietal and occipital lobes was higher for NP. Lacerations were observed only for penetrating gun in the cortical region of frontal and parietal lobes. Subarachnoid haemorrhage surrounding the brainstem and laceration in the midbrain and pons was only found for P3. Thus, penetrating captive bolt gun operating with 190 psi is more effective to achieve unconsciousness.

Teat order affects postweaning behaviour in piglets / A ordem da teta afeta o comportamento pós-desmame em leitões

The objective of this study was to investigate if piglets that suck anterior teats differ from the others in the litter in birth weight, if they have higher growth rate during lactation, and if this affects behaviour and post-weaning weight gain, when piglets change to a solid diet. For this, the teat order of 24 litters was determined during suckling. Piglets were weaned on the 28^thday of age, and 24 groups were formed, composed of one piglet that sucked on the first two pairs of teats (AT) and three piglets that sucked on the other teats (OT). Even though weight at birth did not vary according to teat order, weight gain at weaning differed between the groups (AT: 6.64, S.E. 0.20kg, OT: 5.73, S.E. 0.13kg; P<0.001). After weaning, AT piglets spent more time lying (P<0.01) and less time eating (P<0.01) and vocalizing (P<0.01), than the other piglets. Other behaviours (agonistic interaction, escape attempt and drinking) did not differ between the groups. Piglets that sucked anterior teats gained more weight until weaning, suggesting they took in more milk; this fact might have lead them to have less contact with solid food before weaning, influencing their post-weaning alimentary behaviour.

O objetivo deste estudo foi verificar se leitões que mamam nas tetas anteriores diferem dos demais da leitegada no peso ao nascimento e tem maior taxa de crescimento durante a lactação, e se isso influencia o comportamento e ganho de peso pós-desmame, quando os leitões passam a receber dieta exclusivamente sólida. Para isso, a ordem da teta foi determinada durante a fase de amamentação em 24 leitegadas. Aos 28 dias de idade, os leitões foram desmamados e foram formados 24 grupos, compostos por um leitão que mamava nos dois primeiros pares de tetas (AT) e três leitões que mamavam nas demais tetas (OT). Embora o peso ao nascimento não tenha diferido de acordo com a ordem da teta, o ganho de peso até o desmame diferiu entre os grupos (AT: 6,64, EP 0,20kg, OT: 5,73, EP 0,13kg; P<0,001). Após o desmame, AT passaram mais tempo em repouso (P<0,01) e menos tempo comendo (P<0,01) e vocalizando (P<0,01), quando comparado com os demais. Outros comportamentos (interação agonística, tentativa de fuga e bebendo) não diferiram entre os grupos. Os leitões que mamavam nas tetas anteriores ganharam mais peso até o desmame, o que sugere que ingeriam mais leite; isso pode ter levado a um menor contato com alimento sólido antes do desmame, por sua vez, influenciando o comportamento alimentar pós-desmame