Nico Brogna

Use of pure glycerol in fattening heavy pigs.

Eighty Italian Duroc×Italian Large White pigs (BW 42.6±3.37kg) were used to determine the effects of pure glycerol on growth performance and meat quality of heavy pigs. Pigs were divided into five groups receiving 0% (control), 5% or 10% during the growing and finishing phases (42.6-160kg BW) (G+F5,G+F10) or 5% or 10% during the finishing period (100-160kg BW) (FIN5,FIN10) of pure glycerol in substitution for maize meal (on a dry matter basis). The pigs were slaughtered at approximately 160kg BW. The growth performance of pigs fed 5% glycerol did not differ from controls regardless of feeding duration, whereas those fed 10% glycerol showed reduced growth and poorer feed:gain ratio. Fat quality and meat suitability for raw ham curing were not affected by dietary treatment. Differences were not consistent enough to draw any conclusion about the effects of feeding glycerol on sensory characteristics.

Performance and fat quality of heavy pigs fed maize differing in linoleic acid content

Maize shows wide differences in linoleic acid due both to total lipid content and to fatty acid profile. Therefore, diets containing the same high maize percentage (up to 55%) can differ in linoleic acid content and lead to subcutaneous fats of differing suitability for raw ham curing. Two trials were performed on heavy pigs; in the first, 60 pigs (body weight 48.7+/-5.1 kg) were fed three diets made using three maize batches differing in linoleic acid due to different total lipid content, in the second trial, 40 pigs (live weight 70.4+/-3.4 kg) were fed two diets made using two maize batches differing in linoleic acid due to their fatty acid profile. Pigs were slaughtered at 170 kg of live weight. In both trials, the growth and slaughtering performance did not differ. In the first trial the three diets lead to a different content of linoleic acid both in subcutaneous (low linoleic vs medium linoleic vs high linoleic P0.01) and intramuscular fat (low linoleic vs high linoleic P0.05). In the second trial different linoleic acid content was observed for subcutaneous fat (P0.01) but not for intramuscular fat. To formulate diets for heavy pigs, it is crucial to know the linoleic acid content of the maize used, because differences of only 0.3% can lead to significant differences in fatty acids composition of depot fats.

Effects of a soybean-free diet supplied to Italian heavy pigs on fattening performance, and meat and dry-cured ham quality

The aim of this study was to investigate the effects of a diet containing non-conventional (i.e. alternative to soybean meal) vegetable protein sources on fattening performance, and meat and dry-cured ham quality of heavy pigs. Fifty-six (Landrace x Large White) castrated males with an initial average body weight of 50 kg were allocated to two experimental groups: a control group in which pigs received a traditional soybean meal-based diet, and a treatment group in which soybean meal was replaced by vegetable protein sources (i.e. sunflower meal, potato protein, corn gluten feed, faba beans and dehydrated alfalfa meal), mainly locally grown and not genetically modified. Pigs were slaughtered at approximately 160 kg body weight. Dietary treatment had no significant effect on fattening performance, or meat, fat or dry-cured ham properties. Results suggest that it is possible to feed heavy pigs a soybean-free diet without impairing fattening performance or the quality of meat and Italian PDO (Protected Designation of Origin) hams.

The use of near-infrared reflectance spectroscopy (NIRS) in the prediction of chemical composition and in vitro neutral detergent fiber (NDF) digestibility of Italian alfalfa hay.

Abstract The objective of the present work was to develop calibration equations for the prediction of chemical composition and forage digestibility from different populations of alfalfa hay harvested in Parmigiano-Reggiano cheese production area of Northern Italy. Due to annual climatic variations that affect soil and growing conditions and consequently cause high variability in chemical and physical composition, 319 hay samples from four years were used to build robust calibration. NIRS calibration equations were developed for the prediction of in vitro NDF digestibility (IVNDFd) and 20 chemical parameters (dry matter, starch, fat, sugar, fiber fractions, crude protein, nitrogen fractions and some minerals) of Italian hay. The results obtained show that NIRS equations greatly explain the variation in the composition existing in alfalfa hays grown in Northern Italy, except for a few parameters characterized by low variability range value. The equations obtained for the prediction of biological and chemical parameters explain the major part of the variation existing in the reference data, which open great prospects for the use of NIRS in planning feeding strategies of livestock, based on alfalfa forage.

Effect of dietary supplementation with methionine on cheese-making properties

Riassunto Effetto dell’integrazione della dieta con metionina sulle caratteristiche casearie del latte. Sono stati messi a confronto due gruppi omogenei di bovine in lattazione che hanno ricevuto diete ipoproteiche (13% S.S.) integrate o meno con DL-metionina ruminoprotetta. I risultati dimostrano che bassi tenori proteici ottenuti con diete prive di soia sono compatibili con elevate produzioni. Nel latte l’urea si mantiene bassa (20 mg/100 ml) e la qualità dello stesso risulta buona. L’integrazione delle diete ipoproteiche con metionina stimola la produzione ma, verosimilmente per un effetto “diluizione”, ne riduce significativamente il contenuto di proteine e di lattosio. Le caratteristiche casearie non risultano influenzate (eccezion fatta per l’acidità) dalla metionina ma le rese in formaggio sono inferiori nel gruppo trattato. In ogni caso la quantità stimata di formaggio prodotto dalle vacche trattate è leggermente superiore in relazione alla produzione media giornaliera più elevata.

Technical note: Near infrared reflectance spectroscopy to predict fecal indigestible neutral detergent fiber for dairy cows

In vitro and in situ procedures performed to estimate indigestible neutral detergent fiber (iNDF) in forage or fecal samples are time consuming, costly, and limited by intrinsic factors. In contrast, near infrared reflectance spectroscopy (NIRS) has become widely recognized as a valuable tool for accurately determining chemical composition and digestibility parameters of forages. The aim of this study was to build NIRS calibrations and equations for fecal iNDF. In total, 1,281 fecal samples were collected to build a calibration data set, but only 301 were used to develop equations. Once dried, samples were ground and chemically analyzed for crude protein, ash, amylase and sodium sulfite-treated NDF corrected for ash residue (aNDFom), acid detergent fiber, acid detergent lignin, and in vitro digestion at 240 h to estimate iNDF (uNDF240). Each fecal sample was scanned using a NIRSystem 6500 instrument (Perstorp Analytical Inc., Silver Spring, MD). Spectra selection was performed, resulting in 301 sample spectra used to develop regression equations with good accuracy and low standard error of prediction. The standard error of calibration (SEC), cross validation (SECV), and coefficients of determination for calibration (R2) and for cross validation (1 - VR, where VR = variance ratio) were used to evaluate calibration and validation results. Moreover, the ratio performance deviation (RPD) and ratio of the range of the original data to SECV (range/SECV; range error ratio, RER) were also used to evaluate calibration and equation performance. Calibration data obtained on fiber fractions aNDFom (R2 = 0.92, 1 - VR = 0.87, SEC = 1.48, SECV = 1.89, RPD = 2.80, and RER = 20.19), uNDF240 (R2 = 0.92, 1 - VR = 0.86, SEC = 1.65, SECV = 2.24, RPD = 2.57, and RER = 14.30), and in vitro rumen aNDFom digestibility at 240 h (R2 = 0.90, 1 - VR = 0.85, SEC = 2.68, SECV = 3.43, RPD = 2.53, and RER = 14.0) indicated the predictive equations had good predictive value.

Assessment of muscle Longissimus thoracis et lumborum marbling by image analysis and relationships between meat quality parameters

The intramuscular fat (IMF), recognized by the consumer as marbling, is an important meat quality trait. The objective of this study was to validate a new method of beef marbling evaluation by image analysis. The new assessment was compared with two known marbling measurements: chemical IMF and USDA scores. Moreover, the relationship between marbling measurements and other meat quality parameters was investigated. Samples of Longissimus thoracis et lumborum (LTL) muscle were obtained from carcasses of 39 Italian crossbred heifers and 62 Angus bred heifers, that underwent two different dietary treatments. The use of various breeds and diets was chosen to obtain different intramuscular fat levels, in order to validate the use of Image J software for the analysis of different type of beef meat. The images of fresh cuts were appraised by experienced beef graders, and the samples were used to determine fat content by chemical Soxhlet extraction. Carcasses measurements according to the EUROP system, and other physical meat proprieties were also assessed. The results demonstrated that the marbling measurements obtained by computer image analysis, such as the number of marbling particles, the average particle size (mm), and the percentage of marbling particles (%), significantly (P < 0.05) correlated with USDA scores and IMF content. Moreover, the principal component analysis (PCA) showed three principal meat components, identified as 1) color, 2) fat, and 3) water release. The second principal component (PC) explained 24.94% of variance, and was positively correlated with image analysis measures, USDA score, and IMF, while negatively correlated with the Warner–Bratzler shear force (WBSF).

Effect of dietary inclusion of different lipid supplements on quality and oxidative susceptibility of beef meat

Abstract The aim of this study was to evaluate the impact of dietary extruded flaxseed (EF) and/or rumen-protected (rp) lipids on beef meat quality and oxidation. In all, 63 crossbred heifers (Charolais × Limousin) were evenly distributed into seven experimental groups, balanced in terms of age and body weight (BW). The feeding groups differed in both, the dietary lipid source (EF and/or rp-conjugated linoleic acid (CLA), supplemented with vitamin E (VE)) and the supplementation length (90 or 180 days before slaughter); the same total amount of lipids was administered to the animals. With the respect of the control group, the α-linolenic acid content significantly increased and the n-6/n-3 ratio decreased in cattle groups fed with EF. The results also show that providing CLA and/or EF did not lead to an increase in CLA isomers (CLAs) in the lipid fraction of the meat. Our finding shows that administering EF for a shorter period with respect to longer, moderately enhance the nutritional value of the meat with regard to fat composition. No significant effects of dietary supplementation on TBA-reactive substances (TBARs) levels of fresh meat were observed; however, the protection provided by vitamin supplementation might become evident during meat storage under commercial retail conditions.