Effect of hazelnut skin by-product supplementation in lambs' diets: Implications on plasma and muscle proteomes and first insights on the underlying mechanisms.

This study aimed to evaluate the effect of hazelnut skin by-product supplementation on lamb meat quality characteristics and plasma and muscle proteomes. Twenty-two Valle del Belice male lambs were divided into two experimental groups: control (C), fed a maize-barley diet and hazelnut (H), fed hazelnut skin by-product as maize partial replacer in the concentrate diet. The meat of lambs fed hazelnut skin showed greater values of lightness, redness, yellowness, and chroma color parameters together with the highest myofibril fragmentation index. Two-dimensional electrophoresis and mass spectrometry applied on plasma proteome identified 20 protein spots corresponding to 18 unique gene names to be differently expressed due to hazelnut skin by-product substitution. For the early post-mortem muscle, 23 protein spots (42 unique gene names) were significantly up-regulated due to hazelnut skin by-product supplementation. Four proteins these being APOA1, PHB, ACTG1 and ALB, were found to be common to the two proteomes suggesting that these proteins could be candidate biomarkers to monitor in vita and post-mortem lamb meat quality traits. This study evidenced the main mechanisms involved in the supplementation of hazelnut skin by-product in lambs' diet and confirmed the possibility of using plasma proteome as a non-invasive way to predict lamb meat quality. SIGNIFICANCE: Maximizing the use of agro-industrial by-products as replacers of traditional feedstuff for improving animal products is one of the important challenges to preserving natural resources and guaranteeing environmental sustainability. Hazelnut (Corylus avellana L.) skin, obtained as a results of hazelnut roasting, represents a valuable by-products due to its high content in unsaturated fatty acids, tannins, and vitamins. Thus, including hazelnut skin by-product in small ruminant nutrition could reduce the costs of animal feedings for farmers as well as improve meat nutritional and sensorial characteristics. Additionally, monitoring the meat quality characteristics with fast, accurate, and non-invasive tools to find, before slaughter, animals with desired quality characteristics is of growing interest in the last years. In this regard, the objectives of this study were to assess i) the effect of hazelnut skin supplementation on lamb meat quality characteristics and plasma and muscle proteomes, and ii) whether analyzing plasma proteome by using a gel-based proteomic approach could effectively offer a more readily available option for determining lamb meat quality. Taken together, the proteomic approach applied to plasma and muscle proteomes, allowed us to reveal the pathways and the potential candidate plasma biomarkers to predict lamb meat production in the pre-slaughter phase.

Effect of dietary magnolia bark extract supplementation in finishing pigs on the oxidative stability of meat.

BACKGROUND: Magnolia bark extract (MBE) is a natural supplement with antioxidant, anti-inflammatory, and antimicrobial activities. Its properties suggest that the dietary supplementation in livestock could improve the quality of products. Therefore, the aim of this study was to investigate, for the first time, the effect of dietary MBE supplementation (0.33 mg/kg) in finishing pigs on the oxidative stability of meat. Oxidative stability is of paramount importance for pork, as it affects storage, retail, and consumer acceptance. For the purpose, the fatty acid profile, cholesterol, fat-soluble vitamins, antioxidant enzymes (catalase, glutathione peroxidase, and superoxide dismutase), non-enzymatic antioxidant capacity (TEAC, FRAP, and Folin-Ciocalteu assays), color stability, and lipid stability of pork were assessed. RESULTS: Concerning carcass characteristics, dietary MBE did not affect cold carcass yield, but reduced (P = 0.040) the chilling weight loss. The meat from pigs fed MBE had a lower (P = 0.031) lightness index than the control meat. No effect on intramuscular fat, cholesterol, and fatty acid profile was observed. Dietary MBE did not affect the content of vitamin E (α-tocopherol and γ-tocopherol) in pork, whereas it reduced (P = 0.021) the retinol content. The catalase activity was 18% higher (P = 0.008) in the meat from pigs fed MBE compared with the control group. The MBE supplementation reduced (P = 0.039) by 30% the thiobarbituric acid reactive substances (TBARS) in raw pork over 6 d of aerobic refrigerated storage. Instead, no effect on lipid oxidation was observed in cooked pork. Last, the meat from pigs fed MBE reduced Fe3+-ascorbate catalyzed lipid oxidation in muscle homogenates, with a lower (P = 0.034) TBARS value than the control group after 60 min of incubation. CONCLUSIONS: Dietary MBE supplementation in finishing pigs delayed the lipid oxidation in raw meat. This effect was combined with an increased catalase concentration. These results suggest that dietary MBE could have implications for improving the shelf-life of pork.

Effect of different levels of organic zinc supplementation on pork quality.

This study investigated the effect of two supplementation levels of zinc glycinate (ZnGly) on performance, carcass characteristics, and meat quality of growing-finishing pigs. Thirty pigs (bodyweight: 61 ± 4.0 kg) were assigned to three treatments and fed ad libitum for 56 days a diet supplemented with 0 (control), 45 (Zn45), or 100 mg/kg (Zn100) of ZnGly. The highest ZnGly supplementation lowered the average daily gain (P = 0.031); while, cold carcass weight did not differ between treatments. Both ZnGly levels reduced carcass chill loss (P < 0.001). Micromineral content, color stability, and fatty acid profile of meat were not altered by ZnGly. Superoxide dismutase activity was lowered by Zn45 compared to control (P = 0.007); while, catalase activity was enhanced by Zn100 (P = 0.003). Although ZnGly supplementation did not influence lipid oxidation in raw meat and in meat homogenates incubated with pro-oxidant catalysts, Zn45 limited lipid oxidation in cooked meat (P = 0.037). Our results demonstrated that supplementing pigs with 45 mg/kg of ZnGly could improve the oxidative stability of pork subjected to strong pro-oxidant conditions, but this effect needs to be further elucidated.

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.

Fatty acid metabolism in lambs supplemented with different condensed and hydrolysable tannin extracts.

Five groups of lambs (n = 9 each) were used to test the effect of plant extracts rich in hydrolysable (HT) or condensed tannin (CT) on animal performance, fatty acid composition of rumen content, liver and meat. The control group (CO) received a concentrate-based diet without tannins supplementation. The other groups received the same diet as the control lambs plus 4% chestnut (CH) and tara (TA) extracts as a source of HT and mimosa (MI) and gambier (GA) extracts as a source of CT. One-way ANOVA was used to assess the overall effect of dietary treatments, tannins supplementation (CO vs. CH+TA+MI+GA) and the effect of tannin type (HT vs. CT: CH+TA vs. MI+GA) on animal performance, rumen content, liver and intramuscular FA. Dietary CH negatively affected animal performance. The rumen content of the different groups showed similar levels of 18:3 c9c12c15, 18:2 c9c12, 18:2 c9t11, 18:1 t11 and 18:0, whereas 18:1 t10 was greater in CO. Also, 18:1 t10 tended to be lower in the rumen of HT than CT-fed lambs. These data were partially confirmed in liver and meat, where CO showed a greater percentage of individual trans 18:1 fatty acids in comparison with tannins-fed groups. Our findings challenge some accepted generalizations on the use of tannins in ruminant diets as they were ineffective to favour the accumulation of dietary PUFA or healthy fatty acids of biohydrogenation origin in the rumen content and lamb meat, but suggest a generalized influence on BH rather than on specific steps.

Concentrate supplementation with dried corn gluten feed improves the fatty acid profile of longissimus thoracis muscle from steers offered grass silage.

BACKGROUND: Concentrate supplementation of a grass silage-based ration is a typical practice employed for indoor winter finishing of beef cattle in many temperate countries. Plant by-products, such as dried corn gluten feed (CGF), can be used to replace conventional feedstuffs in a concentrate supplement to enhance the sustainability of ruminant production systems and to improve meat quality. This study examined the chemical composition, fatty acid profile, oxidative stability and sensory attributes of beef (longissimus thoracis muscle) from steers offered grass silage and concentrate supplements containing varying levels (0%, 25%, 50%, 75%) of CGF substituted for barley / soybean meal. RESULTS: Feeding 50%CGF decreased the protein content and increased intramuscular fat in comparison with 25%CGF. Total phenol content and iron-reducing antioxidant power followed the order: 0%CGF > 50%CGF and 25%CGF > 0%CGF = 50%CGF, respectively. Compared to 0%CGF, 25%CGF and 75%CGF decreased C14:0 and increased C22:2n-6, C20:5n-3 and total n-3 polyunsaturated fatty acids whereas 75%CGF increased conjugated linoleic acids and C18:3n-3. Diet did not affect the oxidative stability and sensory attributes of beef patties. CONCLUSION: The inclusion of up to 75%CGF in a supplementary concentrate for steers increased the proportion of health-promoting unsaturated fatty acids without negatively influencing the shelf-life and eating quality of longissimus thoracis muscle. © 2021 Society of Chemical Industry.

Fatty acid composition, shelf-life and eating quality of beef from steers fed corn or wheat dried distillers' grains with solubles in a concentrate supplement to grass silage.

Thirty-six steers were randomly assigned to one of three dietary treatments fed ad libitum grass silage and concentrate supplements containing either barley/soybean meal (CON), 80% DM corn (CDGS)- or 80% DM wheat (WDGS)-dried distillers' grains with solubles for 124 days pre-slaughter. Chemical and fatty acid composition, shelf-life, and eating quality of longissimus thoracis muscle were determined. Dietary CDGS and WDGS increased the proportion of conjugated linoleic acids (P < 0.05) and tended to increase C18:3n-3 (P = 0.075) and total polyunsaturated fatty acids (P = 0.060) relative to the CON. Feeding diets containing distillers' grains reduced the lipid and colour stability of fresh beef patties stored in modified atmosphere packs (MAP), with CDGS exhibiting an intermediate effect between CON and WDGS. Diet did not negatively influence the texture profile parameters and eating quality attributes of beef stored in MAP. The inclusion of CDGS or WDGS in supplementary concentrates may improve the fatty acid profile but decreased the shelf-life of beef.

Quality indices and sensory attributes of beef from steers offered grass silage and a concentrate supplemented with dried citrus pulp.

This study investigated the quality composition, oxidative stability and sensory attributes of beef (longissimus thoracis, LT) from steers offered grass silage and a concentrate supplement in which barley was replaced by 40% and 80% (as-fed basis) of dried citrus pulp (DCP). Dietary treatment did not influence the antioxidant status (α-tocopherol and total phenolic contents) and activities of LT (radical scavenging activity, ferric reducing antioxidant power and iron chelating activity). Feeding DCP significantly increased the proportion of conjugated linoleic acids and polyunsaturated fatty acids in beef. Lipid and colour stability of fresh beef patties stored in modified atmosphere packs (MAP) were unaffected by dietary treatment but feeding 40% DCP reduced (P < .05) lipid oxidation in aerobically-stored cooked beef patties. Beef patties stored in MAP for up to 7 days were assessed by sensory panellists to be juicier for those fed 40% DCP compared to 0% and 80% DCP. Results indicated that substitution of barley with DCP improved the fatty acid profiles of beef without negatively influencing the eating quality of beef.

Hazelnut as Ingredient in Dairy Sheep Diet: Effect on Sensory and Volatile Profile of Cheese.

The opportunity of replacing expensive feedstuffs with agro-industrial by-products in the diet of food producing animals is raising increasing interest while addressing global concern for the scarcity of natural resources and environmental impact of livestock farming. Hazelnut peels, rich in fiber and vitamins and characterized by a high concentration of fats, is considered a suitable ingredient to be included in the diet of ruminants. The aim of this research was to assess the effect of dietary hazelnut peels on the chemical and sensory properties of sheep cheese during refrigerated storage. To this purpose, 20 Comisana lactating ewes were randomly assigned to two experimental groups, control (C) and hazelnut peels (HP), balanced for parity, milk yield and body weight. Bulk milk collected from the 2 groups was used to produce 5 Pecorino cheeses for each group. After 40 d of aging, each cheese of each experimental group was divided into 3 pieces: 1 piece was sampled for analyses (C0, HP0) and 2 were wrapped in PVC film, simulating the condition of pre-wrapped products, and analyzed after 7 (C7, HP7) and 14 days of storage (C14, HP14) at 8°C with 80% moisture. The cheeses were analyzed for chemical and fatty acid composition, sensory analysis, odor active compounds and SmartNose. As expected, HP cheeses presented a higher lipid content compared to C, a lower content in SFA and PUFA, and a greater content in MUFA. A triangle test revealed a clear distinction between the 2 groups (α = 0.01) The sensory profile showed a significant effect on holes (P < 0.05) and a marginal production of off-flavors linked to spicy and acid attributes for HP cheeses The volatile profile of C and HP cheese samples showed a good similarity, partially explained by the short ripening time and the absence of 2-nonanone in HP7, suggesting a higher antioxidant protection grade of this cheese compared to the others. These results were confirmed by Smart Nose analysis. Further studies on vitamin content should be conducted in order to investigate the interactions between the presence of antioxidant volatile compounds and the oxidative stability of ewe cheese.

Dried tomato pomace supplementation to reduce lamb concentrate intake: Effects on growth performance and meat quality.

The effect of dried tomato pomace (DTP) was tested on lamb performances, meat fatty acids and oxidative stability. For 36 days, one group of lambs (n = 7; CON) was fed a commercial concentrate, while the other group (n = 7; DTP) received DTP in addition to CON diet. The administration of DTP reduced (P < .05) concentrate intake, with no effect on animal performances. The DTP treatment tended to increase total polyunsaturated fatty acids (PUFA; P = .075), PUFA n-6 (P = .071), α-linolenic acid (P = .096) and increased linoleic acid (P < .05), γ-tocopherol (P < .001) and retinol (P < .001) in meat. In raw meat, DTP treatment increased L* (P = .059), b* (P < .05), C* (P = .052) and H* (P < .05) values compared to CON, while lipid oxidation was not affected. In meat homogenates incubated with pro-oxidants, DTP tended to reduce 2-thiobarbituric acid reactive substances (TBARS; P = .088). Therefore, DTP supplementation decreased the consumption of commercial concentrate without detrimental effects on animal performances and meat quality traits.

Characterisation of the ruminal fermentation and microbiome in lambs supplemented with hydrolysable and condensed tannins.

This study characterised the response of ruminal fermentation and the rumen microbiome in lambs fed commercial vegetal sources of hydrolysable tannins (HT) and condensed tannins (CT). Forty-four lambs (19.56 ± 2.06 kg) were randomly assigned to either a concentrate diet (CON, n = 8) or CON supplemented with 4% of two HT [chestnut (Castanea sativa, HT-c) and tara (Caesalpinia spinosa, HT-t)] and CT [mimosa (Acacia negra, CT-m) and gambier (Uncaria gambir, CT-g)] extracts (all, n = 9) for 75 days pre-slaughter. Tannin supplementation did not influence ruminal fermentation traits. Quantitative PCR demonstrated that tannins did not affect the absolute abundance of ruminal bacteria or fungi. However, CT-m (-12.8%) and CT-g (-11.5%) significantly reduced the abundance of methanogens, while HT-t (-20.7%) and CT-g (-20.8%) inhibited protozoal abundance. Ribosomal amplicon sequencing revealed that tannins caused changes in the phylogenetic structure of the bacterial and methanogen communities. Tannins inhibited the fibrolytic bacterium, Fibrobacter and tended to suppress the methanogen genus, Methanosphaera. Results demonstrated that both HT and CT sources could impact the ruminal microbiome when supplemented at 4% inclusion level. HT-t, CT-m and CT-g extracts displayed specific antimicrobial activity against methanogens and protozoa without compromising ruminal fermentation in a long-term feeding trial.

Dietary citrus pulp improves protein stability in lamb meat stored under aerobic conditions.

The antioxidant effects of dried citrus pulp on proteins in lamb meat, when used as a replacement of concentrate in the feed, was studied using meat from 26 male Comisana lambs. The lambs of age 90 days had been grouped randomly to receive one of the three dietary treatments: (1) commercial concentrate with 60% barley (Control, n=8), (2) concentrate with 35% barley and 24% citrus pulp (Cp24, n=9), or (3) concentrate with 23% barley and 35% citrus pulp (Cp35, n=9). Slices from the longissimus thoracis et lomborum muscle were packed aerobically and stored for up to 6days at 4°C in the dark. The citrus pulp groups, Cp24 and Cp35, significantly decreased protein radicals and carbonyls, and preserved more thiols within six days of storage compared to the Control group. The citrus pulp groups significantly slowed down the rate of protein oxidation, indicating that dietary citrus pulp reduced oxidative changes in meat proteins.

The antioxidant status and oxidative stability of muscle from lambs receiving oral administration of Artemisia herba alba and Rosmarinus officinalis essential oils.

The effect of the dietary supplementation to lambs of essential oils (EOs) from rosemary (Rosmarinus officinalis) and artemisia (Artemisia herba alba) on the antioxidant status of muscle and on meat oxidative stability was studied. Eighteen Barbarine lambs were divided into 3 groups and for 95days received oat hay and concentrates. One group (C) was not supplemented, while the other two groups received 400mg/kg of EOs from rosemary (R400) or artemisia (A400). Both EOs possessed antioxidant properties and their oral administration improved the reducing and radical scavenging capacity of the muscle compared to the C treatment (P<0.01). Nevertheless, supplementing EOs did not exert protection against lipid oxidation and did not affect the colour stability in meat over 7days of aerobic storage.

Effect of the dietary supplementation of essential oils from rosemary and artemisia on muscle fatty acids and volatile compound profiles in Barbarine lambs.

Eighteen Barbarine lambs (3 months of age), were assigned for 95 days to 3 treatments: six lambs were fed a barley-based concentrate plus oat hay ad libitum (control group, C); other lambs received the control diet plus essential oil (400 ppm DM) either of Rosmarinus officinalis (R400 group; n=6) or of Artemisia herba alba (A400 group; n=6). At slaughter the muscle longissimus dorsi was sampled and subjected to fatty acid and volatile organic compounds (VOC) analyses. The A400 lambs presented a greater amount of vaccenic, rumenic and linolenic acids and of polyunsaturated fatty acids (PUFA) in meat than the C and R400 animals. Essential oils supplementation did not affect meat VOC profile though the sesquiterpenes copaene and ß-caryophyllene were detected only in the meat of R400 and A400 lambs. It is concluded that the supplementation of rosemary or artemisia essential oils does not produce detrimental effects on lamb meat VOC profile. The supplementation of artemisia can improve meat healthy properties.

Dietary quebracho tannins are not absorbed, but increase the antioxidant capacity of liver and plasma in sheep.

A total of sixteen lambs were divided into two groups and fed two different diets. Of these, eight lambs were fed a control diet (C) and eight lambs were fed the C diet supplemented with quebracho tannins (C+T). The objective of the present study was to assess whether dietary quebracho tannins can improve the antioxidant capacity of lamb liver and plasma and if such improvement is due to a direct transfer of phenolic compounds or their metabolites, to the animal tissues. Feed, liver and plasma samples were purified by solid-phase extraction (SPE) and analysed by liquid chromatography-MS for phenolic compounds. Profisitinidin compounds were identified in the C+T diet. However, no phenolic compounds were found in lamb tissues. The liver and the plasma from lambs fed the C+T diet displayed a greater antioxidant capacity than tissues from lambs fed the C diet, but only when samples were not purified with SPE. Profisetinidin tannins from quebracho seem not to be degraded or absorbed in the gastrointestinal tract. However, they induced antioxidant effects in animal tissues.

Bacterial and protozoal communities and fatty acid profile in the rumen of sheep fed a diet containing added tannins.

This study evaluated the effects of tannins on ruminal biohydrogenation (BH) due to shifts in the ruminal microbial environment in sheep. Thirteen lambs (45 days of age) were assigned to two dietary treatments: seven lambs were fed a barley-based concentrate (control group) while the other six lambs received the same concentrate with supplemental quebracho tannins (9.57% of dry matter). At 122 days of age, the lambs were slaughtered, and the ruminal contents were subjected to fatty acid analysis and sampled to quantify populations of Butyrivibrio fibrisolvens, which converts C(18:2) c9-c12 (linoleic acid [LA]) to C(18:2) c9-t11 (rumenic acid [RA]) and then RA to C(18:1) t11 (vaccenic acid [VA]); we also sampled for Butyrivibrio proteoclasticus, which converts VA to C(18:0) (stearic acid [SA]). Tannins increased (P < 0.005) VA in the rumen compared to the tannin-free diet. The concentration of SA was not affected by tannins. The SA/VA ratio was lower (P < 0.005) for the tannin-fed lambs than for the controls, suggesting that the last step of the BH process was inhibited by tannins. The B. proteoclasticus population was lower (-30.6%; P < 0.1), and B. fibrisolvens and protozoan populations were higher (+107% and +56.1%, respectively; P < 0.05) in the rumen of lambs fed the tannin-supplemented diet than in controls. These results suggest that quebracho tannins altered BH by changing ruminal microbial populations.