Effects of clays used as oil adsorbents in lamb diets on fatty acid composition of abomasal digesta and meat

Dietary combination of linseed and hazelnut skin as a sustainable strategy to enrich lamb with health promoting fatty acids

This study investigated the effect of the inclusion of extruded linseed and hazelnut skin on fatty acid (FA) metabolism in finishing lambs. Forty lambs were divided into 4 groups and fed for 60 d with: a conventional cereal-based diet, or the same diet with 8% of extruded linseed, or 15% of hazelnut skin, or 4% of linseed plus 7.5% of hazelnut skin as partial replacement of maize. Dietary treatments did not affect growth performances, carcass traits, and ruminal fermentation. The combined effect of linseed and hazelnut skin enriched the intramuscular fat with health promoting FA. Particularly, increases in α-linolenic acid (3.75-fold), and very long-chain n-3 poly-unsaturated FA (+ 40%) were attributed to the supplementation with linseed, rich in α-linolenic acid. In addition, increases in rumenic (+ 33%), and vaccenic (+ 59%) acids were attributed to hazelnut skin tannins modulating ruminal biohydrogenation and accumulating intermediate metabolites. The simultaneous inclusion of linseed and hazelnut skin can be a profitable strategy for enriching the intramuscular fat of lambs with health promoting FA, without adverse effects on ruminal fermentation and animal performance.

The Effect of Saponite Clay on Ruminal Fermentation Parameters during In Vitro Studies

Reducing the emission of global warming gases currently remains one of the strategic tasks. Therefore, the objective of our work was to determine the effect of saponite clay on fermentation in the rumen of cows. The pH, total gas production, CH4, and volatile fatty acid (VFA) production in ruminal fluid was determined in vitro. Saponite clay from the Tashkiv deposit (Ukraine) has a high content of silicon, iron, aluminum, and magnesium. The addition of 0.15 and 0.25 g of saponite clay to the incubated mixture did not change the pH but reduced the total production (19% and 31%, respectively) and CH4 (24% and 46%, respectively) in the ruminal fluid compared to the control group and had no significant effect on the total VFA levels, but propionic acid increased by 15% and 21% and butyric acid decreased by 39% and 32%, respectively. We observed a decrease in the fermentation rates, with a simultaneous increase in the P:B ratio and an increase in the fermentation efficiency (FE) in the groups fermented with saponite clay, probably a consequence of the high efficiency in the breakdown of starch in the rumen. Therefore, further in vivo studies to determine the effective dose and effect of saponite clay on cow productivity and the reduction of gas emissions are promising and important.

Chestnut tannin extract modulates growth performance and fatty acid composition in finishing Tan lambs by regulating blood antioxidant capacity, rumen fermentation, and biohydrogenation

Tannins as plant extracts have emerged as promising and potential alternatives for antibiotics in modern livestock cultivation systems. This study investigates the effect of dietary chestnut tannin extract (CTE) in finishing Tan lambs. Twenty-seven male Tan lambs were randomly divided into three groups: (1) control group (CON; basal diet); (2) low-dose CTE group (LCTE; basal diet + 2 g/kg CTE, dry matter [DM] basis); (3) high-dose CTE group (HCTE; basal diet + 4 g/kg CTE, DM basis). The HCTE group exhibited markedly higher average daily gain (ADG) and DM intake than CON (P < 0.01). The ruminal total volatile fatty acid concentration increased linearly with increasing CTE supplementation (P < 0.01), while the opposite trend was observed for butyrate molar proportion (P < 0.01). Upon increasing CTE dosage, plasma glucose, high-density lipoprotein cholesterol, glutathione peroxidase, and superoxide dismutase content increased linearly (P < 0.05), whereas low-density lipoprotein cholesterol and urea nitrogen decreased linearly or quadratically (P < 0.05), respectively. A linear increase was also observed in ruminal t6 C18:1 and t9, c12 C18:2 proportions (P < 0.01), and plasma C18:2n-6 and n-6 polyunsaturated fatty acids proportions with increased CTE supplementation (P < 0.01). In the longissimus dorsi muscle, the atherogenic index decreased linearly (P < 0.05), while c11 C18:1 and C20:5n-3 increased linearly (P < 0.05). Moreover, c9, t11 conjugated linoleic acids proportion increased in subcutaneous fat with CTE supplementation (P < 0.01). In conclusion, Dietary CTE enhances the ADG of finishing Tan lambs in a dose-dependent manner, modulates plasma metabolites and antioxidant capacity, and improves rumen fermentation and body fatty acid composition. These results provide a reference for the rational application of CTE in ruminant production.

Inclusion of Sainfoin in the Concentrate of Finishing Lambs: Fatty Acid Profiles of Rumen, Plasma, and Muscle

The effects of sainfoin inclusion (Onobrychis viciifolia) in the finishing concentrate for light lambs on the fatty acid (FA) composition of the ruminal digesta, plasma, and meat were evaluated. Twenty-six weaned male lambs were divided into three groups and fed individually ad libitum for 40 days with one of three concentrates differing in the level of sainfoin inclusion: 0% (0SF), 20% (20SF), and 40% (40SF). The rumen digesta showed an increase in C18:3 n-3 concentration and a decrease in C18:1 t10 concentration when sainfoin was included in the concentrate regardless of the level of inclusion. However, the highest C18:1 t11 and the lowest C18:2 n-6 proportions were obtained only in the 40SF rumen, showing a stronger t11 biohydrogenation pathway. In plasma, most effects were associated with changes in the levels of polyunsaturated FA (PUFA) n-3. The meat FA profile of 40SF lambs presented higher percentages of PUFA n-3 and CLA c9,t11 and a lower PUFA n-6/PUFA n-3 ratio compared with those from 0SF and 20SF diets because of the potentiation of the ruminal t11 pathway. Inclusions of 20 and 40% sainfoin both showed beneficial effects on meat quality; furthermore, these effects were most marked in the 40% sainfoin diet.

Effect of Dioscorea Opposite Waste Supplementation on Antioxidant Capacity, Immune Response and Rumen Microbiome in Weaned Lambs

Dioscorea opposite waste (DOW) has been shown to improve the gastrointestinal microbiome, antioxidation capacity, and immune activity, indicating it is a potential feed resource to improve the physiological health and rumen function of weaned lambs. In the present study, the responses of rumen microbiome to DOW supplementation in diet were profiled using metagenome sequencing. In addition, the potential of DOW to regulate plasma parameters in weaned lambs and its possible mechanisms were investigated. Sixty healthy male small tail Han lambs (22.68 ± 2.56 kg) were selected and equally assigned to four dietary treatments: (1) DOW-free diet (CON), (2) addition of 10% DOW diet (DOW1), (3) addition of 15% DOW diet (DOW2), and (4) addition of 20% DOW diet (DOW3). Experimental lambs were fed a corresponding diet for 62 days. Rumen microbiome and plasma parameters were determined at the end of the experiment. The results showed that dietary supplementation with DOW linearly increased the concentration of aspartate aminotransferase, alkaline phosphatase, Immunoglobulin A, Immunoglobulin M, Immunoglobulin G, Glutathione peroxidase, Superoxide dismutase, and total antioxidant capacity in the plasma of weaned lambs, but an opposite trend was observed in Interleukin-1β, Interleukin-6, tumor necrosis factor-α, and Malondialdehyde between the DOW-supplemented group and the CON group. Sequencing of rumen metagenome revealed that dietary supplementation with 20% DOW significantly affected the microbial composition and function and increased the richness and diversity of rumen microbiota and relative abundance of phylum Verrucomicrobia, Planctomycetes, Fibrobacteres, Chloroflexi, Actinobacteria, and Acidobacteria and species Ruminococcaceae_bacterium, Clostridiales_bacterium_NK3B98, Clostridiales_bacterium, and Clostridia_bacterium. It was concluded that supplementing the weaned lamb’s ration with DOW increased the immune response and antioxidant capacity in a dose-dependent manner. Meanwhile, dietary supplementation with 20% DOW modulated the composition of rumen microbiome function by increasing Ruminococcaceae_bacterium and Clostridiales_bacterium with improving the polysaccharide hydrolase activity in the rumen.

Effects of Dietary Babassu Oil or Buriti Oil on Nutrient Intake and Total Tract Digestibility, and Abomasal Digesta Fatty Acid Profile of Lambs

Simple Summary

This research tested the effects of adding babassu oil (450 g/kg C12:0 of total fatty acids—FA) or buriti oil (750 g/kg C18:f total FA) to the diet of lambs on intake, nutrient digestibility, FA profile of abomasal digesta content and biohydrogenation patterns in digestive content. Both are widely available in the Northeast of Brazil and Amazon region. Our results provide evidence that the babassu supplemented diet promotes greater stress to the ruminal bacteria (due to the high concentration of C12:0), changing the normal biohydrogenation of polyunsaturated FA (PUFA) in the rumen, and the FA concentration that flows to the abomasum, compared to the buriti oil supplemented diet, which provided similar results to the non-supplemented diet.

Abstract

Our current understanding of the effect of medium-chain FA (MCFA) rich vegetable oils on ruminant nutrition is limited. We assessed the effects of babassu or buriti oil addition to the diet of lambs on intake, nutrient digestibility, FA profile of abomasal digesta content and biohydrogenation (BH) patterns in digestion. The experimental diets were defined by the addition of babassu oil or buriti oil to the diet, as follows: (1) non-supplemented diet (CON); (2) 40 g/kg of babassu oil (BAO, rich in C12:0); and (3) 40 g/kg of buriti oil (BUO, rich in c9 18:1), on a dry matter (DM) basis. During the last five days of the feedlot, samples of orts and feces were individually collected to determine the nutrient and FA digestibility. At the end of the experiment, animals were slaughtered, and the abomasal digesta was collected, freeze-dried and used for FA determinations conducted by gas chromatography. The BAO diet decreased the DM (p = 0.014) and nutrient intake. The lambs fed BUO had the greatest FA intake, followed by the BAO and CON diets. However, BAO increased total FA digestibility, compared with CON, but did not differ from BUO. The BAO diet extensively changed the FA composition of abomasal digesta when compared with both the CON and BUO diets. The BAO diet also increased C12:0 and C14:0, the sum of PUFA and the BH intermediates FA, including the t-10-18:1 but decreased the C18:0 in abomasal digesta. The BUO addition had the greatest total-FA and C18:0 and the lowest biohydrogenation intermediate content in abomasal digesta. The BH was less complete with the BAO diet and a large increase in t10-18:1 and of t10-/t11-18:1 ratio was observed, which indicates the occurrence of t10 possibly shifted rumen BH pathways, probably as a response to bacterial membrane stress induced by the greater C12:0 concentration in the rumen.

Effects of calcium salt of linseed oil fatty acid with different oil adsorbents on in vitro gas production and ruminal fermentation characteristics

We investigated the effects of supplementary calcium salt of fatty acid (CSFA) from linseed oil with different oil adsorbents on in vitro gas production and rumen fermentation characteristics in barley substrate condition. A non-supplementation treatment (CONT) and treatments of six products, CSFA without oil adsorbent (2.1 fatty acid/Ca molar ratio) and CSFAs with silica gel, zeolite, bentonite, diatomite, and vermiculite (2.8 fatty acid/Ca molar ratio), were prepared. The supplementary 2% and 4% CSFA with silica gel (+S) in the substrate reduced CH₄ production 56% and 79%, respectively, compared with that in CONT (p < 0.01). The products, except for +S, did not decrease CH₄ production. The dry matter (DM) disappearance in CSFAs with oil adsorbents was lower than that in the CSFA without oil adsorbent (74.8%-77.3% vs. 79.3%, p < 0.01), and crude protein (CP) disappearance in +S supplementation was lower than that of the other products (53.5% vs. 57.2%-59.1%, p < 0.01). The +S supplementation decreased acetate proportion and increased propionate proportion (p < 0.01). Our study indicated that although the disappearance of DM and CP might decrease, using silica gel as an oil adsorbent of linseed oil calcium salt with high fatty acid/Ca molar ratio has the potential to mitigate CH₄ emissions from ruminants.

Effect of dietary buriti oil on the quality, fatty acid profile and sensorial attributes of lamb meat

Forty crossbred (Santa Ines × Dorper) male lambs were used to investigate the effect of dietary buriti oil (BOIL) intake on meat quality, fatty acid (FA) composition and sensory attributes. A completely randomized design with five BOIL intake levels (0, 12, 24, 36 and 48 g/kg DM) was used. Increasing dietary BOIL intake linearly reduced the DMI, slaughter weight, cooking loss, shear force, yellowness, 16:0, c9-18:1 FA concentrations, and the delta-9-desaturase activity index computed using c9-16:1 and 16:0 as product and substrate pair, cis-MUFA and ƩMUFA/ƩSFA ratio of lamb meat (P ≤ 0.05); however, increasing dietary BOIL intake quadratically increased the energy intake, lipid content and linearly increased the total FA intake, chroma, collagen, total BI, 18:0, 20:3n-6 concentration and sensory attributes of lamb meat (P ≤ 0.05), without affecting health indexes regarding fat consumption. BOIL addition at levels above 24 g/kg DM in lamb diet reduces growth, however, improves tenderness, flavor and "goat" aroma intensity and slightly changes meat FA levels, promoting better acceptance by panelists.

Freeze-dried Nannochloropsis oceanica biomass protects eicosapentaenoic acid (EPA) from metabolization in the rumen of lambs

Eicosapentaenoic acid (EPA) from freeze-dried biomass of Nannochloropsis oceanica microalgae resists ruminal biohydrogenation in vitro, but in vivo demonstration is needed. Therefore, the present study was designed to test the rumen protective effects of N. oceanica in lambs. Twenty-eight lambs were assigned to one of four diets: Control (C); and C diets supplemented with: 1.2% Nannochloropsis sp. oil (O); 12.3% spray-dried N. oceanica (SD); or 9.2% N. oceanica (FD), to achieve 3 g EPA /kg dry matter. Lambs were slaughtered after 3 weeks and digestive contents and ruminal wall samples were collected. EPA concentration in the rumen of lambs fed FD was about 50% higher than lambs fed SD or O diets. Nevertheless, the high levels of EPA in cecum and faeces of animals fed N. oceanica biomass, independently of the drying method, suggests that EPA was not completely released and absorbed in the small intestine. Furthermore, supplementation with EPA sources also affected the ruminal biohydrogenation of C18 fatty acids, mitigating the shift from the t10 biohydrogenation pathways to the t11 pathways compared to the Control diet. Overall, our results demonstrate that FD N. oceanica biomass is a natural rumen-protected source of EPA to ruminants.

Trans-10 18:1 in ruminant meats: A review

Trans (t) fatty acids (TFA) from partially hydrogenated vegetable oils (i.e., industrial trans) have been phased out of foods in many countries due to their promotion of cardiovascular disease. This leaves ruminant-derived foods as the main source of TFA. Unlike industrial TFA where catalytic hydrogenation yields a broad distribution of isomers, ruminant TFA are enzymatically derived and can result in enrichment of specific isomers. Comparisons between industrial and ruminant TFA have often exonerated ruminant TFA due to their lack or at times positive effects on health. At extremes, however, ruminant-sourced foods can have either high levels of t10- or t11-18:1, and when considering enriched sources, t10-18:1 has properties similar to industrial TFA, whereas t11-18:1 can be converted to an isomer of conjugated linoleic acid (cis(c)9,t11-conjugated linoleic acid), both of which have potential positive health effects. Increased t10-18:1 in meat-producing ruminants has not been associated with negative effects on live animal production or meat quality. As such, reducing t10-18:1 has not been of immediate concern to ruminant meat producers, as there have been no economic consequences for its enrichment; nevertheless at high levels, it can compromise the nutritional quality of beef and lamb. In anticipation that regulations regarding TFA may focus more on t10-18:1 in beef and lamb, the present review will cover its production, analysis, biological effects, strategies for manipulation, and regulatory policy.

Effects of Increasing Doses of Condensed Tannins Extract from Cistus ladanifer L. on In Vitro Ruminal Fermentation and Biohydrogenation

Simple Summary

Ruminant edible products have been associated with adverse health effects, due to their high saturated fatty acids and low polyunsaturated fatty acids content, resulting from the extensive biohydrogenation conducted by rumen microbiota. Cistus ladanifer condensed tannins were able to change the lamb ruminal biohydrogenation, increasing the beneficial fatty acids production. The aim of this study was to test the effect of increasing doses of C. ladanifer condensed tannins extract (0, 25, 50, 75 and 100 g/kg dry matter) on in vitro rumen fermentation and biohydrogenation. The increasing doses of condensed tannins led to a moderate decrease of volatile fatty acids production, a pronounced depression in microbial odd and branched fatty acids and of dimethyl acetals production, and a minor effect on the biohydrogenation, which indicates that microbial growth was more inhibited than fermentative and biohydrogenation activities. The ability of C. ladanifer condensed tannins extract to modulate the biohydrogenation (BH) was not observed in the present study. However, the results obtained suggest a possible adaptative response of the microbial population to stress stimuli of condensed tannins and lipid supplementation.

Abstract

Cistus ladanifer (rockrose) is a perennial shrub quite abundant in the Mediterranean region, and it is a rich source in secondary compounds such as condensed tannins (CTs). Condensed tannins from C. ladanifer were able to change the ruminal biohydrogenation (BH), increasing the t11–18:1 and c9,t11–18:2 production. However, the adequate conditions of the C. ladanifer CTs used to optimize the production of t11–18:1 and c9,t11–18:2 is not yet known. Thus, we tested the effect of increasing the doses of C. ladanifer CT extract (0, 25, 50, 75 and 100 g/kg dry matter (DM)) on in vitro rumen BH. Five in vitro batch incubations replicates were conducted using an oil supplemented high-concentrate substrate, incubated for 24 h with 6 mL of buffered ruminal fluid. Volatile fatty acids (VFAs) and long chain fatty acids (FA) were analyzed at 0 h and 24 h, and BH of c9–18:1, c9, c12–18:2 and c9, c12, c15–18:3, and BH products yield were computed. Increasing doses of C. ladanifer CTs led to a moderate linear decrease (p < 0.001) of the VFA production (a reduction of 27% with the highest dose compared to control). The disappearance of c9–18:1 and c9,c12–18:2 as well as the production of t11–18:1 and c9, t11:18:2 was not affected by increasing doses of C. ladanifer CTs, and only the disappearance of c9, c12, c15–18:3 suffered a mild linear decrease (a reduction of 24% with the highest dose compared to control). Nevertheless, increasing the C. ladanifer CT dose led to a strong depression of microbial odd and branched fatty acids and of dimethyl acetals production (less than 65% with the highest dose compared to control), which indicates that microbial growth was more inhibited than fermentative and biohydrogenation activities, in a possible adaptative response of microbial population to stress induced to CTs and polyunsaturated fatty acids. The ability of C. ladanifer to modulate the ruminal BH was not verified in the current in vitro experimental conditions, emphasizing the inconsistent BH response to CTs and highlighting the need to continue seeking the optimal conditions for using CTs to improve the fatty acid profile of ruminant fat.

Palm oil protects α-linolenic acid from rumen biohydrogenation and muscle oxidation in cashmere goat kids

Background

In ruminants, dietary C18:3n-3 can be lost through biohydrogenation in the rumen; and C18:3n-3 that by-passes the rumen still can be lost through oxidation in muscle, theoretically reducing the deposition of C18:3n-3, the substrate for synthesis of poly-unsaturated fatty acids (n-3 LCPUFA) in muscle. In vitro studies have shown that rumen hydrogenation of C18:3n-3 is reduced by supplementation with palm oil (rich in cis-9 C18:1). In addition, in hepatocytes, studies with neonatal rats have shown that cis-9 C18:1 inhibits the oxidation of C18:3n-3. It therefore seems likely that palm oil could reduce both rumen biohydrogenation of C18:3n-3 and muscle oxidation of C18:3n-3. The present experiment tested whether the addition of palm oil to a linseed oil supplement for goat kids would prevent the losses of C18:3n-3 and thus improve the FA composition in two muscles, Longissimus dorsi and Biceps femoris. To investigate the processes involved, we studied the rumen bacterial communities and measured the mRNA expression of genes related to lipid metabolism in Longissimus dorsi. Sixty 4-month-old castrated male Albas white cashmere kids were randomly allocated among three dietary treatments. All three diets contained the same ingredients in the same proportions, but differed in their fat additives: palm oil (PMO), linseed oil (LSO) or mixed oil (MIX; 2 parts linseed oil plus 1 part palm oil on a weight basis).

Results

Compared with the LSO diet, the MIX diet decreased the relative abuandance of Pseudobutyrivibrio, a bacterial species that is positively related to the proportional loss rate of dietary C18:3n-3 and that has been reported to generate the ATP required for biohydrogenation (reflecting a decrease in the abundance of rumen bacteria that hydrogenate C18:3n-3 in MIX kids). In muscle, the MIX diet increased concentrations of C18:3n-3, C20:5n-3, C22:6n-3, and n-3 LCPUFA, and thus decreased the n-6/n-3 ratio; decreased the mRNA expression of CPT1β (a gene associated with fatty acid oxidation) and increased the mRNA expression of FADS1 and FADS2 (genes associated with n-3 LCPUFA synthesis), compared with the LSO diet. Interestingly, compared to Longissimus dorsi, Biceps femoris had greater concentrations of PUFA, greater ratios of unsaturated fatty acids/saturated fatty acids (U/S), and poly-unsaturated fatty acids/saturated fatty acids (P/S), but a lesser concentration of saturated fatty acids (SFA).

Conclusions

In cashmere goat kids, a combination of linseed and palm oils in the diet increases the muscle concentration of n-3 LCPUFA, apparently by decreasing the relative abundance of rumen bacteria that are positively related to the proportional loss rate of dietary C18:3n-3, by inhibiting mRNA expression of genes related to C18:3n-3 oxidation in muscle, and by up-regulating mRNA expression of genes related to n-3 LCPUFA synthesis in muscle, especially in Longissimus dorsi.

Effects of the dietary inclusion of babassu oil or buriti oil on lamb performance, meat quality and fatty acid composition

The effects of adding babassu oil (BAO) or buriti oil (BUO) to lamb diets, on performance, carcass characteristics, meat quality and fatty acid (FA) composition were evaluated. Feeding BAO reduced (P = .02) dry matter intake, kidney fat and dressing percentage, but did not change energy intake and performance. Meat pH, color, protein content and sensorial evaluation were not affected by diet. However, BUO increased (P = .02) intramuscular and subcutaneous fat contents, but decreased shear force. BAO increased (P < .05) trans-monounsaturated FA, total biohydrogenation intermediates (BHI) and the t10:t11 ratio, in meat and subcutaneous fat, but decreased total FA and cis-monounsaturated FA, did not change SFA, and increased (P = .04) PUFA in meat. BUO supplementation promoted the highest (P < .05) SFA and total FA content in subcutaneous fat but did not change PUFA. BAO can be used as an alternative energy source for growing lambs, but does not improve the meat FA composition.

Inclusion of the aerial part and condensed tannin extract from Cistus ladanifer L. in lamb diets - Effects on growth performance, carcass and meat quality and fatty acid composition of intramuscular and subcutaneous fat

Thirty-six lambs were used to evaluate the effect of three levels of Cistus ladanifer condensed tannins (CT; 0, 1.25 and 2.5%) and two ways of CT supply (C. ladanifer aerial parts and C. ladanifer CT extract) on lamb growth performance, carcass composition, meat quality and FA composition of intramuscular and subcutaneous fat. The basal diet was composed of dehydrated lucerne supplemented with 60 g/kg of soybean oil. The highest amount of CT (2.5%) had detrimental effects on growth performance, particularly when the aerial part of C. ladanifer was used. Conversely, 1.25% CT in diets did not affect growth performance and meat quality, and inclusion of C. ladanifer CT extract in diet at this level increased t11-18:1, but not c9,t11-18:2 content in fat. Feeding C. ladanifer CT extract might be a good approach for enhancing the nutritional value of ruminant fat, but further studies are needed to ensure upregulation of endogenous synthesis of c9,t11-18:2.

Effect of dietary neutral detergent fibre source on lambs growth, meat quality and biohydrogenation intermediates

With this trial we have tested the effects of structural and chemical composition of neutral detergent fibre (NDF) of the diet on lamb fatty acid composition of meat and subcutaneous fat. Twenty lambs, were fed complete diets with low starch and similar NDF content of different origin (ground alfalfa or soybean hulls). Animal performance and product quality were not affected by treatments. Rumen pH increased and parakeratosis intensity decreased with the level of alfalfa in the diet. Increasing the alfalfa proportion in the diet decreased t10-18:1 (P = .023), increased t11-18:1 (P = .003) and decreased the t10/t11 ratio according to a quadratic pattern (P = .020). Chemical composition and structure of the diet's fibrous fraction influenced the BI pattern of the final product. Forty percent of alfalfa in diet reduced the severity of t10-shift, but for its full resolution, other factors should be considered including forage particle size and buffering capacity of the diet.

Effects of Condensed and Hydrolyzable Tannins on Rumen Metabolism with Emphasis on the Biohydrogenation of Unsaturated Fatty Acids

The hypothesis that condensed tannins have higher inhibitory effect on ruminal biohydrogenation than hydrolyzable tannins was tested. Condensed tannin extract from mimosa (CT) and hydrolyzable tannin extract from chestnut (HT) or their mixture (MIX) were incorporated (10%) into oil supplemented diets and fed to rumen fistulated sheep. Fatty acid and dimethyl acetal composition of rumen contents and bacterial biomass were determined. Selected rumen bacteria were analyzed by quantitative real time PCR. Lower ( P < 0.05) rumen volatile fatty acids concentrations were observed with CT compared to HT. Moreover, lower concentration ( P < 0.05) of Fibrobacter succinogenes, Ruminococcus flavefaciens, Ruminococcus albus, and Butyrivibrio proteoclasticus were observed with CT compared to HT. The extension of biohydrogenation of 18:2n-6 and 18:3n-3 did not differ among treatments but was much more variable with CT and MIX than with HT. The trans-/ cis-18:1 ratio in bacterial biomass was higher ( P < 0.05) with HT than CT. Thus, mimosa condensed tannins had a higher inhibitory effect on ruminal metabolism and biohydrogenation than chestnut hydrolyzable tannins.

The reduction of starch in finishing diets supplemented with oil does not prevent the accumulation of trans-10 18:1 in lamb meat

The experiment was conducted to test the hypothesis that the replacement of cereal with low-starch feed ingredients in lambs' finishing diets supplemented with oils could prevent the accumulation of -10-18:1 in meat. Forty lambs were fed 1 of 4 diets supplemented with soybean oil (5.9%) and fish oil (1%) for 6 wk before slaughter. The control (CON) diet contained 43% barley, and in the other diets, barley was completely replaced by dehydrated citrus pulp (DCP), dehydrated sugar beet pulp (DBP), or soybean hulls (SH). Growth performance, feed intake, and carcass and meat quality traits were analyzed. At slaughter, LM samples were collected for gene expression evaluation, and 3 d after slaughter, LM and subcutaneous (s.c.) fat samples were collected for fatty acid analysis. None of the diets affected meat quality, but the DCP diet reduced ADG ( < 0.05) and the DCP and SH diets decreased the feed-to-gain ratio ( < 0.01). The DCP diet increased ( < 0.05) the risk of parakeratosis and the severity of the lesions. Moreover, the DBP treatment led to increased a* (redness) and b* (yellowness) in s.c. fat compared with the CON treatment ( < 0.05). The lipid content of LM did not differ ( > 0.05) with treatment and averaged 34.4 g/kg of meat. Diets had no effect ( > 0.05) on SFA, PUFA, and -MUFA sums and on the -6:-3 ratio in both LM and s.c. fat. A lower expression of fatty acid synthase (FASN) was found with the DCP treatment than with the other treatments ( < 0.001). All treatments showed a high accumulation of -10-18:1, averaging 91 mg/g fatty acid in LM and 147 mg/g fatty acid in s.c. fat. The concentration of -11-18:1 in the tissues was considerably lower than that of -10-18:1, and thus the -10-18:1:-11-18:1 ratio was above 3 with all treatments. Despite this, the SH diet clearly promoted a larger deposition of -11-18:1 and -9,-11-18:2 in tissues compared with the other treatments. () gene expression and SCD activity index in LM were reduced with the SH diet compared with the CON and DCP diets. Overall, these results clearly showed, for the first time, that low-starch/high-NDF diets are not able to prevent the establishment of -10 shifted rumen biohydrogenation pathways, evaluated by the deposition of biohydrogenation intermediates in lamb meat and fat.

Nutritional enhancement of sheep meat fatty acid profile for human health and wellbeing

Dietary fatty acids (FA) consumed by sheep, like other ruminants, can undergo biohydrogenation resulting in high proportions of saturated FA (SFA) in meat. Biohydrogenation is typically less extensive in sheep than cattle, and consequently, sheep meat can contain higher proportions of omega (n)-3 polyunsaturated FA (PUFA), and PUFA biohydrogenation intermediates (PUFA-BHI) including conjugated linoleic acid (CLA) and trans-monounsaturated FAs (t-MUFA). Sheep meat is also noted for having characteristically higher contents of branched chain FA (BCFA). From a human health and wellness perspective, some SFA and trans-MUFA have been found to negatively affect blood lipid profiles, and are associated with increased risk of cardiovascular disease (CVD). On the other hand, n-3 PUFA, BCFA and some PUFA-BHI may have many potential beneficial effects on human health and wellbeing. In particular, vaccenic acid (VA), rumenic acid (RA) and BCFA may have potential for protecting against cancer and inflammatory disorders among other human health benefits. Several innovative strategies have been evaluated for their potential to enrich sheep meat with FA which may have human health benefits. To this end, dietary manipulation has been found to be the most effective strategy of improving the FA profile of sheep meat. However, there is a missing link between the FA profile of sheep meat, human consumption patterns of sheep FA and chronic diseases. The current review provides an overview of the nutritional strategies used to enhance the FA profile of sheep meat for human consumption.

Modulation of in vitro rumen biohydrogenation by Cistus ladanifer tannins compared with other tannin sources

BACKGROUND

Tannins are polyphenolic compounds able to modify the ruminal biohydrogenation (BH) of unsaturated fatty acids, but their activity may vary among different tannin sources. The effect of rockrose (Cistus ladanifer) on BH has never been compared with other more common tannin sources. Tannin extracts (100 g kg^-1 substrate dry matter) from chestnut (CH), quebracho (QB), grape seed (GS) and rockrose (CL) were incubated in vitro for 6 h with ruminal fluid using as substrate a feed containing 60 g kg^-1 of sunflower oil. A control treatment with no added tannins was also included.

RESULTS

Compared with the control, GS and CL, but not CH and QB, increased (P < 0.05) the disappearance of c9,c12-18:2 with a consequent larger production of c9,t11-18:2 and t11-18:1. However, no differences among treatments (P > 0.05) were observed for the disappearance of c9-18:1 and c9,c12,c15-18:3. The production of 18:0 was not different (P > 0.05) among treatments, although its proportion in the total BH products was lower (P < 0.05) for GS than for the other treatments.

CONCLUSION

Condensed tannins from GS and, to a lesser extent, from CL stimulate the first steps of BH, without a clear inhibition of 18:0 production. © 2016 Society of Chemical Industry.

Effect of dietary starch level and its rumen degradability on lamb meat fatty acid composition

Forty lambs were fed one of four diets supplemented with a linseed and sunflower oil blend but differing in starch level (mid, ≈35 vs. high, ≈50%) and starch rumen degradability (mid, ≈70 vs. high, ≈80%). The effects of diet on growth, carcass traits and meat fatty acid (FA) composition, with emphasis on biohydrogenation intermediates were evaluated. Lambs stayed on trial for 5weeks until slaughter. Treatment had no effect on animal performance and carcass traits. High-degradability diets decreased (P=0.04) meat shear force compared with mid-degradability diets. Lipid content of meat was unaffected by the diet. Mid-starch diets increased (P<0.05) the saturated FA and cis-MUFA but decreased (P<0.05) the trans-MUFA, particularly the t10-18:1, when compared with high-starch diets. The t11-18:1 (0.7% of total FA) and c9,t11-18:2 (<0.3%) remained low and the 18:3n-3 remained high (1.74%) and unaffected by diet.