The effect of the change from a herbage- to a concentrate-based diet on the oxidative stability of raw and cooked lamb meat

Dietary supplementation with natural antioxidants: assessment of growth performance and meat quality in broiler chickens

Exposure to air and light lowers the meat quality of chickens, which is mainly determined by the color alteration and accumulation of detrimental products from lipid oxidation. This study tests the effects of 2 supplements rich in polyphenols, Oxilem (OX) and OxiGem (OG), on broiler Ross 308 performance and meat quality in comparison to a control group (C). A total of 105 one-day-old Ross 308 male chicks were allocated to 21 pens and randomly assigned to 1 of the 3 treatments. The trial lasted 42 d. Individual live weight and feed intake per pen were recorded. Proximate analysis, color, cholesterol content and cholesterol oxidation products (COPs), fatty acids (FAs), volatile aldehydes profile, and secondary oxidation products of meat FAs were determined, with analyses for detecting oxidative alterations conducted on breast burgers preserved for 7 d at 4°C. Birds fed OG grew 7 g/d more than those receiving OX, reaching a higher final weight. After slaughtering, meat from the OX group had a higher yellow index compared to C. After 7 d of air and light exposure, the influence on the color parameters of the OG and OX burgers was significantly less pronounced than that of C. Secondary oxidation products of the FAs of the burgers were not significantly affected by the diet regimens. In addition, OX and OG burgers exhibited lower amounts of volatile aldehydes, triol and COPs. These results confirm the effectiveness of OX and OG supplementation against lipid oxidation at the inclusion level used in this trial.

Influence of Dietary Inclusion of Exhausted Bergamot By-Product in Pigs on Animal Performance, Fatty Acid Profile and Oxidative Stability of Meat and Meat Products

An investigation was carried out on the effect in pig diet of supplementation with exhausted bergamot by-product, stemming from pharmaceutical industry after extraction of phenolic compounds, on growth performance and on the quality of meat and meat products. Twenty pigs were assigned to two dietary treatments and fed a conventional concentrate (control) or a concentrate including exhausted bergamot by-product at the level of 15% on a DM basis (EB). No significant differences between dietary treatments were found for final weight (p = 0.243), carcass weight (p = 0.679), dry matter intake (p = 0.321). In EB pork, the proportion of docosapentaenoic acid was significantly increased (p < 0.05); it tended to have a greater proportion of n-3 PUFA (p = 0.09), and the n-6/n-3 PUFA ratio was lower in EB treatment (p = 0.01). In salami from EB pigs fed, the proportion of α-linolenic acid and the total n-3 PUFA were higher than in the control group (p < 0.001). In salami, the TBARS value was lower after 5 days of storage (p < 0.001) in the EB group. Therefore, the present results suggest that the inclusion of exhausted bergamot by-product in pig diet resulted in a qualitative improvement of meat and meat products.

Effect of feeding pigs with bergamot by-product on fatty acid composition and oxidative stability of meat and salami

This work investigated the effects of feeding ensiled bergamot pulp to pigs on meat and salami quality. Eighteen pigs were assigned to two experimental treatments and fed a cereal-based concentrate diet (control) or the same diet in which ensiled bergamot pulp replaced 15% dry matter of the diet fed (BP). The BP treatment increased α-linolenic acid (+250%; P < 0.05), docosapentaenoic acid (+62%; P < 0.05), docosahexaenoic acid (+43%; P < 0.05) and consequently n-3 PUFA (+15%; P < 0.01) in meat. In salami, the content of α-linolenic acid, total PUFA and n-3 PUFA increased (+320%, +25% and + 258%, respectively) by feeding the BP diet (P < 0.001). The inclusion of bergamot pulp in the diet did not alter the oxidative stability in raw and cooked meat and colour descriptors. In salami, TBARS values were lower after 5 days of storage (P < 0.001) in BP group (1.54 vs 2.96). Finally, dietary supplementation with ensiled bergamot pulp to pigs improved the nutritional value of meat and meat products.

Effects of sous vide vs grilling methods on lamb meat colour and lipid stability during cooking and heated display

The present study compared the effect of grilling (150 °C until 72 °C core temperature) and sous-vide (SV) cooking (75 °C for 35 min in a water bath under vacuum) on lamb patties immediately after cooking and after 4 h display at 65 °C. Both methods produced patties with similar (P > 0.05) weight loss, and moisture and fat contents. SV-cooking prevented (P < 0.05) the formation of thiobarbituric acid reactive substances (TBARS) and oxysterols compared to grilled patties, which showed a larger proportion of highly peroxidisable polyunsaturated fatty acids. Heated display induced dehydration, surface darkening and a reduction in the hexanal/3-methylbutanal ratio, suggesting the progression of Maillard reactions. Moreover, TBARS and some lipid oxidation-derived volatiles increased (P < 0.001), while cooked-meat aroma compounds were reduced (P < 0.001). SV-cooking inhibited (P < 0.05) the formation of malondialdehyde, and 7α- and 7β-hydroxycholesterol, and lowered the cholesterol oxidation ratio during heated display. Overall, SV-cooking may be considered a healthier way of cooking when lamb meat is to be kept warm for considerable periods before consumption.

Feeding lambs with silage mixtures of grass, sainfoin and red clover improves meat oxidative stability under high oxidative challenge

This study investigated the oxidative stability of meat from lambs fed silages in which timothy grass was totally or partially replaced by sainfoin and/or red clover. Five groups of 8 lambs were fed the following silages: timothy grass (T), mixture (50:50) of timothy with either sainfoin (T-SF) or red clover (T-RC), mixture of timothy, sainfoin and red clover (50:25:25; T-SF-RC), or mixture (50:50) of sainfoin and red clover (SF-RC). Feeding the silages containing red clover (T-RC, T-SF-RC and SF-RC) decreased the deposition of vitamin E in muscle relative to the highly unsaturated fatty acids (P < .001), did not affect the oxidative stability of fresh meat, but reduced oxidative deterioration in cooked meat and in meat homogenates incubated with pro-oxidant catalysts (P < .001). The results of this study demonstrated that feeding lambs with silages containing sainfoin and red clover improve the oxidative stability of meat subjected to strong pro-oxidant conditions and suggest that these effects should be further clarified.

Effects of feeding juniper as a roughage on feedlot performance, carcass measurements, meat sensory attributes, and volatile aroma compounds of yearling Rambouillet wethers1,2

The majority of U.S. lambs are born during late winter or early spring, which can create downstream variability in carcass quality if commercial lamb harvest is to be relatively constant throughout the year. Flavor is an important quality determining characteristic of sheep meat and is influenced, in part, by animal age at harvest. However, management practices to mitigate the risk of objectionable flavors in meat from old crop lambs or yearlings are not well known. Yearling (16.8 ± 0.14 mo) Rambouillet wethers were assigned to 1 of 3 treatment groups, which consisted of feeding a 20% ground sorghum-sudangrass hay diet for 40 d (JUN0; n = 10), a 20% ground juniper diet for 40 d (JUN40; n = 10), or a 20% ground hay diet for 20 d followed by a 20% ground juniper diet for 20 d (JUN20; n = 10). Wethers were harvested on day 41 and a whole bone-in loin and a boneless inside leg roast were fabricated from one side each of carcass. After grilling (loin chop) or convection air roasting (leg roast), trained sensory panel evaluation and measurement of aroma volatiles by gas chromatography/mass spectrometry were performed. Treatment diet did not affect (P ≥ 0.17) wether feedlot performance, dressing percentage, or loin eye area. However, wethers fed JUN0 tended (P = 0.06) to have greater back fat depth than wethers fed JUN20 or JUN40. No trained sensory panel trait of loin chop samples was affected (P > 0.10) by treatment. Leg roasts from JUN0 and JUN20 wethers had greater (P = 0.01) lamb identification sensory score than JUN40. Benzaldehyde, 1-heptanol, and 1-octanol concentrations were greater (P < 0.05) and decanal and nonenal concentrations were less (P < 0.05) in loin chops from JUN0 compared with JUN40 wethers. Additionally, the terpenes cedr-8-ene, gamma muurolene, and widdrene tended to be greater (P < 0.07) in loin chops from JUN20 and JUN40 than JUN0 wethers. The 2-pentyl-furan concentrations were greatest (P = 0.03) in leg roasts from JUN40 wethers. Like the loin chops, cedr-8-ene, gamma-muurolene, toluene, and widdrene were greater (P < 0.05) in leg roasts from wethers fed either of the juniper diets compared with JUN0. Yearling wethers can be finished on a feedlot diet containing 20% juniper for up to 40 d prior to harvest with no impact on feedlot performance, carcass characteristics, nor negative impact on sensory attributes or volatile compounds of either grilled loin chops or roasted legs.

Effects of feeding legume-grass pasture and different concentrate levels on fatty acid profile, volatile compounds, and off-flavor of the M. longissimus thoracis

Pasture-finished beef is becoming more popular among consumers due to concerns related to fatty acid content and sustainable practices. The effects of finishing crossbred steers on legume-grass pasture comprised of oats, ryegrass, and clover (PAST), legume-grass pasture plus whole corn grain (WCG) supplementation (SUPP), and only with WCG (GRAIN) on fatty acids profile, volatile compounds, sensory, and texture attributes were studied. Pasture diets (PAST and SUPP) led to lower n-6/n-3 ratio (P < 0.001), and highest deposition of C18:2 cis-9 trans-11 (P < 0.001) in the lean. Beef from steers fed GRAIN had the highest values of volatile compounds associated with lipid oxidation. Off-flavor intensity was significantly greater on beef from steers fed GRAIN when compared to PAST. Overall, muscles from steers finished on PAST and SUPP showed similar attributes but differ when compared to GRAIN. The presence of forage is essential to improve fatty acid profile, decrease volatile compounds associated with lipid oxidation, and minimize off-flavor.

Carcass characteristics, physicochemical changes and oxidative stress indicators of meat from sheep fed diets with coffee pulp

The purpose of this study was to determine how feeding sheep coffee pulp affects carcass characteristics and what changes occur in physicochemical, antioxidant capacity and oxidation of the meat during refrigerated storage. The experiment was carried out in 15 Blackbelly lambs weighing an average 22.86±0.76kg. The animals were assigned to three treatments: T0=control diet, T1=diet with 8% coffee pulp, and T2=diet with 16% coffee pulp. After fattening for 56 days, the sheep were slaughtered and the carcasses assessed. The inclusion of 16% coffee pulp in the diet increased carcass dressing from 48.19 to 50.83% and decreased the amount of fat in rumen and intestines from 3.43 to 2.53% (P<0.05). The inclusion of coffee pulp in the diet did not alter the amount of crude protein or fat in meat or its oxidation and antioxidant capacity during refrigerated storage. However, the inclusion of coffee pulp in the diet decreased fat in the rumen and intestines, and thus increased the amount of usable meat.