Fatty acids and oxidative stability of meat from lambs fed carob-containing diets

Dietary hazelnut skin prevents lipid oxidation in lamb enriched in omega-3 polyunsaturated fatty acids

The aim of this study was to investigate the effect of partially replacing maize with hazelnut skin and linseed, alone or in combination, on the oxidative stability of lamb. Forty lambs were randomly assigned to 4 treatments and fed: a conventional cereal-based diet (C), or the same diet with 15 % of hazelnut skin (HS), or 8 % of extruded linseed (LS), or 7.5 % of hazelnut skin plus 4 % of linseed (H + L) as partial replacement of maize. After 60 days of feeding trial, lambs were slaughtered, and hydrophilic antioxidant capacity and fat-soluble vitamins content were evaluated in fresh meat. Colour stability, lipid and protein oxidation were assessed during 7 days of refrigerated storage. Dietary combination of hazelnut skin and linseed increased the content of tocopherols (P < 0.001) and of n-3 polyunsaturated fatty acids (PUFA n-3; P < 0.001), while reducing lipid oxidation (TBARS value) during 7 days of storage (P < 0.001). Feeding lamb with hazelnut skin and/or linseed did not affect meat hydrophilic antioxidant capacity, colour stability, nor the formation of hydroperoxides, thiols, or carbonyls (P > 0.05). These results suggest that vitamin E provided by hazelnut skin contributed to delay lipid oxidation in meat, despite the higher concentration of n-3 PUFA.

Dietary Inclusion of Carob Pulp (Ceratonia siliqua L.) Does Not Replace the Antioxidant Effect of Vitamin E in Lambs' Meat to Lengthen Shelf-Life

The objective of this study was to evaluate the impact of dietary carob pulp (Cp, Ceratonia siliqua L.) and vitamin E (Vit E) on the quality and shelf-life of light lamb meat stored for a maximum of 15 days under modified atmosphere packaging (MAP). Forty-eight lambs (half females and half entire males, 25.3 ± 0.3 kg of body weight and 83 ± 5.8 days old) were randomly selected and slaughtered after an experimental fattening period with a 2 × 2 factorial design: 0 vs. 20% Cp and 40 vs. 300 IU of Vit E/kg of diet for 41 days. The carcass traits, fatty acid (FA) profile, antioxidant content, colour, lipid oxidation, and microbial count in the meat were evaluated. Scarce interactions between Cp and Vit E were observed on most of the variables studied. The dietary inclusion of Cp did not affect carcass traits (p > 0.05) but produced minor changes in the content of branched FA and reduced the α-tocopherol content in the meat (p < 0.05), while no impact was observed on discolouration or lipid oxidation (p > 0.05). High Vit E supplementation increased the yellowness of caudal fat and the α-tocopherol content, which limited discolouration and lipid oxidation (p < 0.05). Furthermore, the High Vit E diet (without Cp) controlled the psychrotrophic bacterial count after 15 days of storage. At slaughter, males were heavier than females but had lower carcass dressing (p < 0.05). The lambs' sex had minor impacts on the quality and shelf-life of meat. This study demonstrated that there is no synergistic interaction between Cp and Vit E on lamb meat quality and shelf-life. Including 20% of Cp in lamb diets is feasible without impairing meat quality. Nevertheless, supplementation with 300 IU of Vit E/kg of feed is essential to extend the shelf-life of meat stored under MAP.

Characterization of Chestnut Tannins: Bioactive Compounds and Their Impact on Lamb Health

The objective of the present study was to characterize the chestnut (Castanea sativa Mill.) tannin product, Farmatan Plus® (Tanin Sevnica d.d., Sevnica, Slovenia), and to subsequently examine its effects on the blood metabolic parameters of fattening lambs, particularly in relation to their health status. Thirty lambs were randomly divided into three treatment groups: a control group without added tannin and two groups that received 9.46 g of the tannin product/kg of the diet dry matter (DM) and 18.87 g of the tannin product/kg of the diet DM. Metabolic parameters such as contents of total protein, globulin, urea, and liver enzymes (AST and GGT) were measured over a trial period of 60 days to evaluate the effects of tannin supplementation. This study represents the first in-depth characterization of Farmatan Plus®, demonstrating its richness in bioactive compounds such as vescalin and castalagin. The results showed no significant adverse effects on lamb health, with all parameters remaining within normal physiological ranges (p > 0.05). These results support the safe inclusion of chestnut tannins in the diet of lambs and underline their potential as a functional feed additive that can positively influence the health and growth performance of ruminants.

Carob (Ceratonia siliqua L.), Pharmacological and Phytochemical Activities of Neglected Legume of the Mediterranean Basin, as Functional Food

Carob (Ceratonia siliqua L.) has been widely cultivated in different parts of the world, particularly in the Mediterranean region, and the tree belongs to the family Leguminosae. Several studies have indicated that carobs and their products can improve human health and help prevent different specific chronic diseases. Carob can considered as functional food due to its high content in dietary fibers, low-fat content, and high content of minerals. Its fruit is a pod containing 10%-20% seeds, and the pods consist of sugars, proteins, crude fibers, minerals, vitamins, polyphenols, vitamins, and lipids. In many countries in the Middle east, carob is mainly used to prepare as a traditional drink and some kinds of confectioneries. The powders can be utilized to prepare carob juice concentrate. The systematic review of documents from clinical trials and scientific societies dedicated to traditional medicine in China has been carried out. The goal of this review article is a survey of chemical compounds, and pharmaceutical benefits of carob, especially by considering traditional medicinal sciences. Moreover, clinical trials research promotes studies to highlight and focus on the scope of application of traditional medicinal science in the growing system of medicine.

Colour Stability, Fatty Acid Profile, and Lipid Oxidation in Meat Stored in Modified Atmosphere Packaging from Light Lambs Fed with Concentrate with Carob Pulp (Ceratonia siliqua L.)

There is a growing interest in using by-products rich in polyphenols, such as carob pulp (Cp, Ceratonia siliqua L.), as a dietary source of antioxidants for animals. This study assesses the effects of including Cp in lambs' diet and meat display time (0, 7, 9, and 11 days) in modified atmosphere packaging on meat colour, fatty acid (FA) composition, tocopherol levels, and lipid oxidation values in the Semimembranosus muscle of 40 light lambs. The lambs were fed with concentrates supplemented with increasing Cp levels (0, 150, and 300 g/kg) for 45 days before slaughter. Metmyoglobin (MMb) and malondialdehyde (MDA) contents increased linearly with display time (p < 0.05), regardless of diet (p > 0.05). At 11 days of display, MMb (28 ± 0.8%) and MDA (0.6 ± 0.1 mg MDA/kg of meat) contents remained within the acceptable limits. The α-tocopherol content was lower in the 30% Cp group and meat (p < 0.05). Total saturated and monounsaturated FA contents (934 ± 64 and 823 ± 65 mg/100 g of meat, respectively) did not differ significantly among the groups. However, the meat from lambs fed with 30% Cp showed reduced levels of branched-chain FAs, while polyunsaturated FAs increased (p < 0.05) compared to the control lambs. The inclusion of Cp in the lamb's diet, up to 30%, did not lead to meat deterioration and improved certain quality parameters, including a healthier FA profile. These findings highlight Cp's potential as an alternative antioxidant source in animal diets.

Feeding hazelnut skin to lambs delays lipid oxidation in meat

This study aimed to investigate the effect of dietary hazelnut skin (HNS), a by-product of confectionery industry, on the oxidative stability of lamb meat. Twenty-two finishing lambs were randomly assigned to 2 groups and fed ad libitum for 56 days on different concentrate-based diets: one control and one experimental, in which 150 g/kg of corn was replaced by HNS. After slaughter, the fat-soluble vitamins content and hydrophilic antioxidant capacity were assessed in fresh meat, as well as color, lipid and protein stability over 7 days of shelf-life trial. Dietary HNS increased (P < 0.001) the tocopherols content of meat and reduced (P < 0.001) lipid oxidation during 7 days of refrigerated storage. Meat from lambs fed HNS showed different (P < 0.05) instrumental color parameters. No diet effect (P > 0.05) was observed on the development of metmyoglobin, hydroperoxides, thiol groups, and carbonyl groups. Feeding HNS to lambs improves the oxidative stability of raw meat by delaying lipid oxidation thanks to the antioxidant molecules (tocopherols and phenolic compounds) contained in this by-product.

Tannin in Ruminant Nutrition: Review

Tannins are polyphenols characterized by different molecular weights that plants are able to synthetize during their secondary metabolism. Macromolecules (proteins, structural carbohydrates and starch) can link tannins and their digestion can decrease. Tannins can be classified into two groups: hydrolysable tannins and condensed tannins. Tannins are polyphenols, which can directly or indirectly affect intake and digestion. Their ability to bind molecules and form complexes depends on the structure of polyphenols and on the macromolecule involved. Tannins have long been known to be an "anti-nutritional agent" in monogastric and poultry animals. Using good tannins' proper application protocols helped the researchers observe positive effects on the intestinal microbial ecosystem, gut health, and animal production. Plant tannins are used as an alternative to in-feed antibiotics, and many factors have been described by researchers which contribute to the variability in their efficiencies. The objective of this study was to review the literature about tannins, their effects and use in ruminant nutrition.

Effect of feeding carob (Ceratonia siliqua L.) pulp powder to broiler chicken on growth performance, intestinal microbiota, carcass traits, and meat quality

In this study, the influence of a partial substitution of corn with carob (Ceratonia siliqua L.) pulp powder on broiler performance, intestinal microbiota, carcass traits, and meat quality, was investigated. Two dietary treatments were compared: the control group received a diet containing basically corn, soybean meal, and wheat bran for all the breeding periods while the experimental group received the same starter diet as the control group and grower and finisher diets containing 3% and 7% of carob pulp powder, respectively. Growth performance (weight gain, feed intake, and feed conversion ratio), carcass traits, lactic acid bacteria, and total coliforms were determined. Physicochemical parameters, proximate composition, fatty acid profiles, lipid oxidation index, and sensory characteristics of broiler thigh and breast muscles were determined. Dietary supplementation with carob pulp powder did not show an effect (P > 0.05) on growth performance and carcass traits except for slaughter yield and breast relative weight. An increase in sum lactic acid bacteria count and a decrease in total coliforms were observed in the experimental group. No effect (P > 0.05) of dietary carob was observed on pH, cooking losses, ash, mineral, and protein contents in breast and thigh muscles from broilers. However, the experimental diet decreased (P < 0.05) moisture and fat contents in thigh muscles but not in breast muscles. Both muscles from the experimental group of birds exhibited lower palmitic and oleic acids contents, and higher linoleic and linolenic acids levels than those from the control group. Whereas the polyunsaturated fatty acid contents in broiler breast and thigh meat was increased by dietary carob, the concentration of lipid oxidation products decreased in this group. The dietary intervention had no significant effect on the sensory profile of breast and thigh muscles. Thus, carob pulp powder can be applied to broiler diet at 7% as a nonconventional feed with no negative impact on growth performance and carcass traits and to increase the degree of unsaturation with no negative impact on oxidative stability or sensory traits.

Influence of Dietary Algae Meal on Lipid Oxidation and Volatile Profile of Meat from Lambs with Competent Reticular Groove Reflex

Dietary lipid sources influence intramuscular fatty acid composition, which in turn may affect the volatile profile of meat. The aim of this work was to investigate the effects of marine algae supplementation (Aurantiochytrium limacinum) on volatile compounds of cooked lamb meat. Forty-eight lambs with 42 days of age were divided into three groups: lambs fed a conventional diet without algae meal supplementation (NOALG), lambs with competent reticular groove reflex (RGR) fed the same diet supplemented with 2.5% marine algae meal mixed in the concentrate (ALGCON), and lambs with competent RGR, receiving the same diet and fed with 2.5% marine algae meal in a milk replacer to bypass the rumen (ALGMILK). Lipid and protein oxidation in raw meat was assessed and volatile compounds in grilled meat were determined. The highest and lowest lipid oxidations were observed in the ALGMILK and NOALG groups, respectively. Protein oxidation was unaffected. Out of 56 identified compounds, 12 volatiles significantly increased in both algae groups and 6 of them exclusively in the ALGCON treatment. Algae meal supplementation and its form of administration, either protected or not from rumen degradation, are important factors to consider in lipid oxidation and the aromatic profile of lamb meat.

Influence of almond hulls in lamb diets on animal performance and meat quality

Almond hulls (AH) were fed to lambs to study effects on performance and meat quality. Thirty Sarda lambs were allotted to three experimental groups and fed for 40 days either a cereal-based concentrate diet (control) or diets in which cereals were replaced with 15% (AH15) or 30% (AH30) almond hulls on a DM basis. Diets did not affect final body weight, dry matter intake, average daily gain, feed conversion ratio or carcass weight. Replacing part of the cereal mix (i.e., barley and maize) with AH did not affect meat fatty acid profiles. After 5 and 7 days of refrigerated storage respectively for cooked and raw meat, AH15 and AH30 treatments reduced meat lipid oxidation (P < 0.001). Our results suggest feeding almond hulls up to 30% in fattening lamb diets can improve meat oxidative stability without compromising growth performance.

Insights into the role of major bioactive dietary nutrients in lamb meat quality: a review

Feed supplementation with α-linolenic acid (ALA) and linoleic acid (LA) increases their content in muscle, ALA increases n-3 polyunsaturated fatty acids and decrease n-6/n-3 ratio in muscle, and LA increases rumenic acid. However, high LA supplementation may have negative effects on lambs’ lipid oxidative stability of meat. When the sources of ALA and LA are fed as fresh forage, the negative effects are counterbalanced by the presence of other bioactive compounds, as vitamin E (mainly α-tocopherol) and polyphenols, which delay the lipid oxidation in meat. There is a wide consensus on the capability of vitamin E delaying lipid oxidation on lamb meat, and its feed content should be adjusted to the length of supplementation. A high dietary inclusion of proanthocyanidins, phenolic compounds and terpenes reduce the lipid oxidation in muscle and may improve the shelf life of meat, probably as a result of a combined effect with dietary vitamin E. However, the recommended dietary inclusion levels depend on the polyphenol type and concentration and antioxidant capacity of the feedstuffs, which cannot be compared easily because no routine analytical grading methods are yet available. Unless phenolic compounds content in dietary ingredients/supplements for lambs are reported, no specific association with animal physiology responses may be established.

Condensed Tannins as Antioxidants in Ruminants-Effectiveness and Action Mechanisms to Improve Animal Antioxidant Status and Oxidative Stability of Products

Condensed tannins (CTs) are widely distributed in plants, and due to their recognized antioxidant activity are considered as possible natural antioxidants for application in ruminant diets. A wide range of CT-rich sources has been tested in ruminant diets, and their effects on animal antioxidant status and oxidative stability of their products are reviewed in the present work. Possible mechanisms underlying the CT antioxidant effects in ruminants are also discussed, and the CT chemical structure is briefly presented. Utilization of CT-rich sources in ruminant feeding can improve the animals' antioxidant status and oxidative stability of their products. However, the results are still inconsistent. Although poorly understood, the evidence suggests that CTs can induce an antioxidant effect in living animals and in their products through direct and indirect mechanisms, which can occur by an integrated and synergic way involving: (i) absorption of CTs with low molecular weight or metabolites, despite CTs' poor bioavailability; (ii) antioxidant action on the gastrointestinal tract; and (iii) interaction with other antioxidant agents. Condensed tannins are alternative dietary antioxidants for ruminants, but further studies should be carried out to elucidate the mechanism underlying the antioxidant activity of each CT source to design effective antioxidant strategies based on the use of CTs in ruminant diets.

Dietary cardoon meal modulates rumen biohydrogenation and bacterial community in lambs

Cardoon meal is a by-product of oil extraction from the seeds of Cynara cardunculus and can serve as a novel alternative feedstuff for ruminants. This study examined the rumen fermentation, biohydrogenation of fatty acids (FA) and microbial community in lambs fed a concentrate diet containing 15% dehydrated lucerne (CON, n = 8) or cardoon meal (CMD, n = 7) for 75 days pre-slaughter. Diets did not influence rumen fermentation characteristics and the abundance of bacteria, methanogens, fungi, or protozoa. Rumen digesta in CMD-fed lambs displayed a higher concentration of total saturated FA and lower total odd- and branched-chain FA and monounsaturated FA. Feeding CMD decreased total trans-18:1 isomer and the ratio of trans-10 to trans-11 C18:1, known as the "trans-10 shift". Amplicon sequencing indicated that the rumen bacterial community in CMD-fed lambs had lower diversity and a higher relative phyla abundance of Proteobacteria at the expense of Bacteroidetes and Fibrobacteres. At the genus level, CMD mediated specific shifts from Prevotella, Alloprevotella, Solobacterium and Fibrobacter to Ruminobacter, suggesting that these genera may play important roles in biohydrogenation. Overall, these results demonstrate that cardoon meal can be used as a feedstuff for ruminants without negatively affecting rumen fermentation and microbiota but its impact on biohydrogenation may influence the FA composition in meat or milk.

Effects of a high-fibre and low-starch diet in growth performance, carcass and meat quality of young Alentejana breed bulls

Growth performance, carcass and meat quality of 16 Alentejana bulls fed for 90 days with a conventional cereal-based (Control) or a high-fibre and low-starch (HFLS) diet were studied. The HFLS diet included 20% alfalfa hay, 4.8% soybean oil, 6% soybean hulls, 6% dehydrated citrus and 6% sugar beet pulps in substitution of grain. Ryegrass hay was offered to a maximum of 20% of total intake in both diets. Bulls were individually housed, weighed every 14 days, and feed intake was registered daily. Average daily weight gain, dry matter intake, carcass and most meat quality traits were not affected by the diet (P > .05). Feeding an HFLS diet, therefore, can improve beef fatty acid profiles without negatively impacting animal performance or meat quality.

Effects of dietary fat sources on the intramuscular and subcutaneous adipose tissue fatty acid composition, and consumer acceptability of lamb

BACKGROUND

Lamb diets can alter the fatty acid (FA) profile of muscle and adipose tissue, which may affect the sensory quality and consumer acceptability of the meat. In this study, lambs received one of four pre-slaughter diets: a barley / maize / soya-based concentrate (C), supplemented with a saturated fat source (Megalac®) (SAT), or supplemented with protected linseed oil (PLO); or a by-product (citrus pulp / distillers' grain / soya-based) diet (BPR). Intramuscular FAs and adipose tissue branched-chain FAs were measured and consumer evaluation (hedonic liking and attribute intensity) was undertaken with cooked lamb.

RESULTS

Compared to the other diets, the BPR diet resulted in a higher muscle concentration and a greater proportion of C18:2n-6, and greater proportions of conjugated linoleic acid (c9,t11-C18:2) and n-6 polyunsaturated FAs (PUFA), whereas the PLO diet resulted in higher muscle proportions of C18:0 and saturated FAs, higher concentrations of C18:3n-3 and n-3 PUFA, and a lower n-6 to n-3 ratio. The consumer acceptability of lamb was not affected by the pre-slaughter diets.

CONCLUSION

Changes in the FA profile of lamb muscle and adipose tissue through the inclusion of sources of saturated fat, protected linseed oil, or by-products in the pre-slaughter diet did not result in consumer detection of significant effects on the acceptability of the cooked meat. © 2020 Society of Chemical Industry.

Effects of feeding increasing levels of grape (Vitis vinifera cv. Pinotage) pomace on lamb shelf-life and eating quality

The study evaluated shelf-life and sensory quality of meat from lambs fed finisher diets containing increasing levels of grape pomace (GP; 0, 5, 10, 15 and 20% GP/kg DM). Color, antioxidant activity and lipid oxidation of the longissimus lumborum were evaluated on different storage times (days 1, 3, 5, 7 and 9) post-slaughter using overwrapped air-permeable packaging. Treatments 0, 10 and 20% GP/kg DM were used for evaluation of protein oxidation and microbial counts on days 1, 5 and 7, while a trained panel assessed the sensory quality on day 1. Diet neither influenced meat color nor sensory quality. Diet × day interactions were observed for antioxidant activity, lipid and protein oxidation. Overall, the 20% GP/kg-diet finished lamb meat had the highest antioxidant activity and the lowest total viable bacterial counts, lipid and protein oxidation values during the shelf-life period. The 20% GP/kg DM in lamb diets, therefore, improved lamb meat shelf-life without negatively affecting sensory quality.

Urine and fecal samples targeted metabolomics of carobs treated rats

Ceratonia siliqua, known as the carob, is considered to be of high nutritional value and of great economic significance due to its unique composition. The beneficial effects of carob against cancer, metabolic syndrome, diabetes, diarrhea, hyperlipidemia and gastro esophageal reflux disease are only a few of its therapeutic actions. Metabolomics-based analysis provides an ultimate tool, for the deciphering of nutritional intervention derived metabolic alterations. In the present study, 16 male Wistar rats were treated with carob powder for a 15-day period. Fecal and urine samples were collected at 5 time points (0, 1, 5, 10 and 15 days). By the applied HILIC-MS/MS method, 63 and 67 hydrophilic metabolites were detected in the fecal and urine samples, respectively, including amino acids, organic acids, sugars, vitamins and other endogenous compounds. A clear group separation based on fecal metabolome was observed after 1 day and 15 days treatment, while only a mild differentiation at day 1 was observed based on urine metabolome. Twenty-one fecal metabolites were responsible for the separation including amino acids and their derivatives, vitamins and organic acids. However, only 7 metabolites were altered in rat urine samples. Metabolic alterations in fecal samples could be attributed to physiological and biochemical adaptations derived from the nutritional intervention. Fecal targeted metabolomics were proven to be suitable for uplifting and highlighting such alterations.

Oxidative stability of beef from steers finished exclusively with concentrate, supplemented, or on legume-grass pasture

The objective of this study was to evaluate the effects of three finishing systems based on concentrate and legume-grass pasture on beef. Steers were finished for 91 days with an exclusively whole corn grain-based (GRAIN) diet, grazed on legume-grass pasture plus 1.4% of body weight of whole corn grain supplementation (SUPP), or grazed on legume-grass pasture (PAST) only. Lipid and myoglobin oxidation, pH, objective color, and α-tocopherol concentrations were evaluated on M. longissimus thoracis steaks. Dietary treatments did not affect pH and minimally affected protein carbonylation. Steaks from steers fed GRAIN were less red, showed higher lipid oxidation during retail display, and higher metmyoglobin formation from day 7 to 13 when compared to PAST. Levels of α-tocopherol were higher in steaks from steers fed diets containing legume and grass. Inclusion of roughage in finishing diets is essential to maintain retail color and prevent lipid and myoglobin oxidation.