L. Lambertini

Effects of selenium source and level of supplementation on the performance and meat quality of lambs.

Objective of this study was to evaluate the performance, the quality and oxidative stability of meat, the total Se and specific selenoamino-acids content of muscle of lambs that were fed diets supplemented from different Se sources and at different levels. Forty-eight Apennine lambs 30day old (12.78±0.94kg) received, during a 63day period, a total mixed ration (TMR) which was either Se unsupplemented (Control group - background only- 0.13mg/kg Se) or supplemented with Na selenite (0.30mg/kg Se as sodium selenite) or selenium enriched yeast (0.30mg/kg and 0.45mg/kg Se as Se-yeast). Growth performance, feed to gain ratio, carcass and meat quality (pH, drip and cooking losses, colour, GSH-Px activity and chemical analysis) did not show any difference between the treatments. Meat colour and oxidative stability during 9 days of refrigerated storage were unaffected by dietary supplementation, suggesting that, at the levels of Se used in this experiment, dietary Se, even from an organic source, had limited potential for reducing lipid oxidation. Selenium supplementation raised the Se content in muscle (P<0.001) with the greatest increase when Se-yeast was fed. Although selenite increased total Se, it did not influence total or specific selenoamino-acids in this tissue. On the contrary, Se-yeast supplementation led to an increase in muscle Se-methionine content. We conclude that Se supplementation can increase significantly muscle Se levels and produce, particularly when Se-yeast is fed, a source of Se enriched meat as Se-methionine.

The effect of journey time and stocking density during transport on carcass and meat quality in rabbits

Four hundred and fifty hybrid commercial rabbits (half males and half females) at the end of their productive cycle (82 days old) were transported in cages (98×52×24cm, length×width×height) at high or low density (75.5 or 49.0kg/m(2) - 15 or 10 animals per cage) on an uncovered truck for 1, 2 or 4h. Live weight before and after transport as well as slaughter data were recorded for each rabbit. A subset of 180 carcasses were evaluated for meat quality on the basis of meat pH, colour (CIELab system), cooking loss, drip loss and shear force. As a representative of the whole carcass muscle/bone ratio, the left hind leg was separated, dissected and its meat analysed in order to determine its water, protein, ash and lipid content. It was found that a longer journey significantly increases the live weight losses (3.3% vs. 2.0% vs. 1.6% for 4, 2 or 1h, respectively; P<0.001), as a result not only of urine and fecal losses, but also of a decrease in carcass weight (P<0.01) during transport. Ultimate pH (pH(u)) was higher and pH drop lower in rabbits transported for 4h compared to those transported for 2h (P<0.05). Moreover, the meat from animals that had undergone the longest journey was more purple-red (P<0.05), darker (P<0.0001), and firmer when raw and showed less cooking loss than meat from those that underwent shorter journeys. Transport density did not influence any of the considered parameters and there was no interaction between transport time and density.

Effects of loading methods on rabbit welfare and meat quality

The effects of different loading methods on the welfare, carcass characteristics and meat quality traits of hybrid commercial rabbits were investigated. 384 male rabbits, 82 days old, were transported from the farm to the slaughterhouse. At the farm, 192 rabbits were loaded onto the truck smoothly (S) and 192 rabbits were loaded roughly (R). The S loading method consisted of carefully placing each rabbit into the transport crates. In the R method, the loading was hurriedly and carelessly executed by the transport operator, throwing each animal into the crates fixed on the truck. Live weight before and after transport as well as slaughter data were recorded for each rabbit, and a subset of 80 carcasses were evaluated for meat quality. Blood samples from 80 rabbits were analysed for haematological and biochemical parameters. A significant neutrophilia (P<0.001), lymphocytopaenia (P<0.001) and an increase in serum aspartate aminotransferase (AST) (P<0.01), alanine aminotransferase (ALT) (P<0.001) and creatine kinase (CK) activities (P<0.001) were recorded in all rabbits after transport, independent of the loading method. A twofold increase in serum corticosterone concentration (6.23 vs. 14.88 ng/mL; P=0.001) was observed in all rabbits following transport. Results suggest that the stress parameters analysed were more influenced by transport and handling itself rather than by the different loading methods. The results showed that there was no adverse effect of loading method on carcass traits. Furthermore, the stress condition evidenced by haematological and biochemical parameters prior to slaughter did not affect meat quality.

Effects of the rearing season on carcass and meat quality of suckling Apennine light lambs.

The aim of this study was to evaluate the effects of the rearing season (autumn vs winter) on the carcass and meat quality of light lambs, obtained according to the traditional farming system usual in central Italy. Eighty carcasses from 60 d+/-3 old unweaned Apennine single birth male lambs, permanently reared indoor, half in autumn (receiving milk from ewes permanently pastured) and half in winter (which dams did never acceded to pasture), were weighed, classified according to the EU classification system for light lambs, and their Longissimus lumborum meat was analysed for pH, colour, drip and cooking losses, proximate composition and fatty acids profile of intramuscular fat. Most of the carcasses fully responded to the 1st quality EU requirements and no effects of the rearing season was evident on carcass characteristics. On the contrary, L. lumborum of lambs born and reared in autumn, receiving milk from ewes permanently pastured, evidenced a lower Lightness L* (P=0.02), a higher Chroma C* (P=0.01), with a higher fat content (P=0.04) than lambs reared in winter, which dams were permanently stall-fed. Moreover the intramuscular fat of the former was characterized by a greater PUFA concentration (P=0.01), a more favourable n-6/n-3 ratio (P<0.001), and a higher CLA content (P<0.001) than the latter, as a result of the difference related to the sheep traditional feeding system.

Effects of Se supplementation on growth rate and blood parameters in lambs

Abstract Forty-eight Appenninica lambs 30 d old received during a 63 d period the same diet (dry unifeed) supplied 4 different mineral premixes differing for their Se sources and levels to obtain the following 4 treatments (on an as fed basis): Control group (T1) - 0mg/kg Se; T2 – 0.30mg/kg Se as sodium selenite; T3 – 0.30mg/kg and T4 – 0.45mg/kg Se as Se yeast (Saccharomyces cerevisiae). Biweekly all the animals were weighed and feed consumption recorded. Moreover, at start (t0) and successively each two weeks (t14, t28, t42, t56), all the animals were blood sampled in order to evaluate plasma and whole blood Se concentration and blood glutathione peroxidase (GSH-Px) and creatine phosphokinase (CPK) activities. Daily weight gain (averaging 166±6g/d) never differed between treatments. Se supplementation increased Se concentration in blood in relation to dietary level (p<0.05) and, compared to selenite, Se yeast seemed more effective to obtain higher concentration in whole blood (P<0.05) but not in plasma. Blood GSH-Px activity was higher in lambs receiving Se supplementation but was not influenced by Se dietary level or source. No effects could be find on blood CPK activity.

Consequences of behaviour on productive performances of rabbits reared in pens

Riassunto Effetti del comportamento sulle prestazioni produttive di conigli allevati in colonia. Scopo della presente ricerca è stato di verificare i riflessi del comportamento sulle prestazioni produttive di conigli in accrescimento stabulati in gabbie bicellulari o in parchetti collettivi su fondo di rete, a pari densità (15 capi/m2) e a diversa numerosità (15 e 30 soggetti per gruppo). Trentasei conigli maschi, 12 per ciascun gruppo sperimentale, scelti a caso in un lotto complessivo di 212 animali sottoposti a sperimentazione, sono stati videoregistrati per un periodo di 16 ore nell’ultima settimana di allevamento, al fine di poterne evidenziare il tempo dedicato a diversi pattern comportamentali. Gli incrementi ponderali sono stati monitorati mediante pesate individuali ogni due settimane, dallo svezzamento (32 d) alla macellazione (82 d). I riscontri dimostrano, rispetto ai soggetti allevati in gabbie tradizionali, una maggiore attività e aggressività nei conigli allevati in colonia, indipendentemente dalla numerosità adottata. Si è potuta evidenziare una correlazione significativa (P<lt;0,01) fra le attività di interazione e di aggressione o di fuga ed i minori accrescimenti realizzati dai conigli allevati in parchetti. In tal senso, la stabulazione alternativa in colonia potrebbe rivelarsi elemento inscindibilmente correlato con situazioni “stressanti” che condizionano negativamente le prestazioni produttive.

Feeding dehydrated alfalfa increases polyunsaturated fatty acids concentration in Marchigiana beef muscle

Riassunto L’alimentazione con erba medica disidratata eleva il contenuto di acidi grassi polinsaturi delle carni di vitelloni di razza Marchigiana. La ricerca è stata eseguita su 20 vitelloni di razza Marchigiana dai 18 ai 21 mesi. Gli animali sono stati distinti in 2 gruppi sperimentali (controllo e trattato) di 10 capi ciascuno ed alimentati con paglia, fieno e mangime fornito a volontà. I vitelloni del gruppo trattato hanno ricevuto un mangime contenente il 20% di medica disidratata mentre quelli del controllo hanno assunto un mangime di analoghe caratteristiche analitiche ma sprovvisto di foraggi disidratati. I risultati mostrano come l’alimentazione con erba medica disidratata innalzi significativamente il contenuto di acidi grassi polinsaturi (P<0,05) ed in particolare di acido linoleico (C18:3n-3; P<0,001) ed arachidonico (C20:4n-6; P<0,01).