Ruminant-derived Food Products Research Articles

Full-fat insect meals in ruminant nutrition: in vitro rumen fermentation characteristics and lipid biohydrogenation

BackgroundThe most used protein sources in ruminant nutrition are considered as having negative impacts in terms of environmental sustainability and competition with human nutrition. Therefore, the investigation of alternative and sustainable feedstuffs is becoming a priority in ruminant production systems.ResultsThis trial was designed to evaluate eight full-fat insect meals (Acheta domesticus – ACD; Alphitobius diaperinus – ALD; Blatta lateralis – BL; Gryllus bimaculatus – GB; Grylloides sygillatus – GS; Hermetia illucens – HI; Musca domestica – MD; and Tenebrio molitor – TM) as potential protein and lipid sources in ruminant nutrition. Fermentation parameters and fatty acids (FA) of rumen digesta after 24-h in vitro ruminal incubation of the tested insect meals were measured and compared with those of three plant-based meals (soybean meal, rapeseed meal and sunflower meal) and fishmeal (FM). Similarly to FM, the insect meals led to a significantly lower total gas production (on average, 1.75 vs. 4.64 mmol/g dry matter—DM), methane production (on average, 0.33 vs. 0.91 mmol/g DM), volatile FA production (on average, 4.12 vs. 7.53 mmol/g DM), and in vitro organic matter disappearance (on average, 0.32 vs. 0.59 g/g) than those observed for the plant meals. The insect meals also led to lower ammonia of rumen fluid, when expressed as a proportion of total N (on average, 0.74 vs. 0.52 for the plant and insect meals, respectively), which could be an advantage provided that intestinal digestibility is high. Differences in ruminal fermentation parameters between the insect meals could be partially explained by their chitin, crude protein and ether extract contents, as well as by their FA profile. In particular, high content of polyunsaturated FA, or C12:0 (in HI), seems to partially inhibit the ruminal fermentations.ConclusionsThe tested full-fat insect meals appear to be potentially an interesting protein and lipid source for ruminants, alternative to the less sustainable and commonly used ones of plant origin. The FA profile of the rumen digesta of ACD, ALD, GB, GS and TM, being rich in n-6 polyunsaturated FA, could be interesting to improve the quality of ruminant-derived food products.

Endocrine disruptors and ovine reproductive development

Summary. Declining fertility and perturbations in reproductive development in a variety of species have been linked to exposure to endocrine disrupting chemicals (EDCs), which are ubiquitous in the environment. Ruminants are largely exposed to such chemicals in sewage sludge fertiliser widely used in animal production systems. This has been investigated experimentally through the deliberate exposure of pregnant ewes to sewage sludge fertilised pastures or control pastures treated with inorganic fertiliser containing no detectable EDCs. Perturbations in the developing fetal hypothalamic–pituitary–gonadal axis have been observed in both male and female fetuses. A sub-population of rams exposed both pre- and post-natally exhibited adversely altered testis development. Periods of developmental sensitivity to EDCs have also been identified. An in vitro culture system for ovine fetal ovaries has shown that mixtures have a greater effect than individual chemicals. The dog provides a sentinel model of human dietary exposure to chemicals in ruminant-derived food products. Evidence of altered fertility and testicular cancer, along with EDC detection in dog testes and pet foods, support this concept. Established rodent models of EDC exposure provide a means to investigate mechanisms and transgenerational effects. Overall, monitoring and in vitro studies carried out in sentinel species and on human tissues, combined with in vivo mechanistic studies carried out in ruminants and rodents, provides a clear picture of the global impact of EDCs on reproductive development. In particular, the ovine model of sewage sludge exposure provides the only currently available "real life" model of exposure to a cocktail of EDCs.

In vitro rumen biohydrogenation kinetics of mixed linoleic and alfa-linolenic acids

Background: Dietary linoleic (LA) and alpha-linolenic (LN) acids are extensively isomerized and hydrogenated by rumen microbes, and this activity can further contribute to the fatty acid profile of ruminant-derived food products. Objective: To evaluate the effects of LA:LN ratio in lipid supplements on the rumen biohydrogenation kinetics of LA and LN, as well as on the trans-vaccenic acid (VA) production, using an in vitro system. Methods: Rumen fluid was collected from a fistulated steer, diluted with incubation buffer, and then incubated with 500 mg of kikuyu grass (Cenchrus clandestinus) supplemented with 16.3 mg of different LA:LN mixtures (100:0, 75:25, 50:50, 25:75 or 0:100). Incubations were performed in triplicate for a period of 0, 2, 4, 6, 8 or 16 hours. Differences between treatments were evaluated in a completely randomized design. Alternatively, computational chemistry was used to determine the changes in the Gibbs free energy (ΔGrxn) at 39 °C for the principal steps of LA and LN ruminal biohydrogenation. Results: Partial replacement of LA by LN decreased the VA concentration and its accumulation rate; it also increased the stearic acid concentration and the rates of transfer from LA to conjugated linoleic acid (CLA), and from CLA to VA. The conversion from CLAto VA(ΔGrxn = -2.65 kJ/mol) was more spontaneousthan that from trans-11, cis-15 octadecadienoic acid (TA) to VA (ΔGrxn = -0.29 kJ/mol). Conclusion: The LA:LN ratio in lipids can modulate LA and LN biohydrogenation (BH) kinetics, as well as the VA production in the rumen.

Alteration of Rumen Bacteria and Protozoa Through Grazing Regime as a Tool to Enhance the Bioactive Fatty Acid Content of Bovine Milk.

Rumen microorganisms are the origin of many bioactive fatty acids (FA) found in ruminant-derived food products. Differences in plant leaf anatomy and chemical composition between cool- and warm-season pastures may alter rumen microorganisms, potentially enhancing the quantity/profile of bioactive FA available for incorporation into milk. The objective of this study was to identify rumen bacteria and protozoa and their cellular FA when cows grazed a warm-season annual, pearl millet (PM), in comparison to a diverse cool-season pasture (CSP). Individual rumen digesta samples were obtained from five Holstein cows in a repeated measures design with 28-day periods. The treatment sequence was PM, CSP, then PM. Microbial DNA was extracted from rumen digesta and sequence reads were produced with Illumina MiSeq. Fatty acids (FA) were identified in rumen bacteria and protozoa using gas-liquid chromatography/mass spectroscopy. Microbial communities shifted in response to grazing regime. Bacteria of the phylum Bacteroidetes were more abundant during PM than CSP (P < 0.05), while protozoa of the genus Eudiplodinium were more abundant during CSP than PM (P < 0.05). Microbial cellular FA profiles differed between treatments. Bacteria and protozoa from cows grazing CSP contained more n-3 FA (P < 0.001) and vaccenic acid (P < 0.01), but lower proportions of branched-chain FA (P < 0.05). Microbial FA correlated with microbial taxa and levels of vaccenic acid, rumenic acid, and α-linolenic acid in milk. In conclusion, grazing regime can potentially be used to alter microbial communities shifting the FA profile of microbial cells, and subsequently, alter the milk FA profile.

Conjugated linolenic acid (CLnA) isomers as new bioactive lipid compounds in ruminant-derived food products. A review

Conjugated linolenic acid (CLnA) isomers as new bioactive lipid compounds in ruminant-derived food products. A review

Relationships between botanical and chemical composition of forages: a multivariate approach to grasslands in the Western Italian Alps

Plant composition of species-rich mountain grasslands can affect the sensorial and chemical attributes of dairy and meat products, with implications for human health. A multivariate approach was used to analyse the complex relationships between vegetation characteristics (botanical composition and plant community variables) and chemical composition (proximate constituents and fatty acid profile) in mesophilic and dry vegetation ecological groups, comprising six different semi-natural grassland types in the Western Italian Alps. Mesophilic and dry grasslands were comparable in terms of phenology, biodiversity indices and proportion of botanical families. The content of total fatty acids and that of the most abundant fatty acids (alpha-linolenic, linoleic and palmitic acids) were mainly associated to nutrient-rich plant species, belonging to the mesophilic grassland ecological group. Mesophilic grasslands showed also higher values of crude protein, lower values of fibre content and they were related to higher pastoral values of vegetation compared to dry grasslands. The proximate composition and fatty acid profile appeared mainly single species dependent rather than botanical family dependent. These findings highlight that forage from mesophilic grasslands can provide higher nutritive value for ruminants and may be associated to ruminant-derived food products with a healthier fatty acid profile. © 2016 Society of Chemical Industry.

Novel polymorphisms in the 5′UTR of FASN, GPAM, MC4R and PLIN1 ovine candidate genes: Relationship with gene expression and diet

We have analyzed the 5′cis-regulatory regions of four genes coding for key proteins involved in lipid metabolism and energy homeostasis in Rasa Aragonesa, Assaf and Roja Mallorquina sheep breeds. We identified 10 novel polymorphisms in the 5′regulatory regions in fatty acid synthase (FASN), glycerol-3-phosphate acyltransferase mitochondrial (GPAM), melanocortin-4 receptor (MC4R) and perilipin (PLIN1) genes. Due to the involvement of these genes in fat quantitative traits and the effect of all polymorphic positions on transcription factors binding sites, we tested all of them in two relevant meat reared breeds which were subjected to different feeding systems. Although no relationship was detected between the mRNA expression level of the candidate genes and the genotypes, additional studies must be conducted in older individuals, since these polymorphisms have been detected by in silico studies to be putatively involved in transcriptional or posttranscriptional regulatory mechanisms. The expression level of GPAM, MC4R and PLIN1 genes was analyzed and compared between feeding groups detecting over expression of adipogenic genes in the intensive groups. These results suggest that nutritional stimulation affects the expression of candidates genes involved in lipid metabolic processes, and therefore the fat quality in meat ruminant-derived food products.

Effect of tanniniferous Terminalia chebula extract on rumen biohydrogenation, ∆9-desaturase activity, CLA content and fatty acid composition in longissimus dorsi muscle of kids

Conjugated linoleic acid, a fatty acid found in milk fat and ruminant meat is one of the functional food components. Modifying fatty acid composition so as to increase CLA and other beneficial PUFA/MUFA level and reducing SFA levels might be a key to enhance the neutraceutical and therapeutic value of ruminant-derived food products. In the present experiment, the effect of supplementation of polyphenol rich Terminalia chebula plant extract at different concentrations (1.06g/kg and 3.18g/kg of body weight in T1 and T2 groups, respectively) was investigated on fatty acid composition of rumen fluid, plasma, intramuscular fat and Δ9-desaturase activity in longissimus dorsi muscle of crossbred kids. Total MUFA and PUFA content in muscle were enhanced by 25 and 35%, respectively, whereas SFA was reduced by 20% thereby improving the desaturation index. Δ9-desaturase activity also increased by 47% resulting in an enhancement of total CLA content (58.73%) in muscle.

Microbial fatty acid conversion within the rumen and the subsequent utilization of these fatty acids to improve the healthfulness of ruminant food products

Consumers are aware of foods containing microcomponents that may have positive effects on health maintenance and disease prevention. In ruminant milk, meat, and milk products; these functional food components include eicosapentaenoic acid (20:5n3), docosahexaenoic acid (22:6n3), 9c11t-conjugated linoleic acid, and vaccenic acid (11t-18:1). Modifying ruminal microbial metabolism of fatty acid in rumen through animal diet formulation is an effective way to enhance these functional fatty acids in ruminant-derived food products. However, it requires an understanding of the interrelationship between supply of lipid through the diet and rumen fermentation. Lipids in ruminant diets undergo extensive hydrolysis and biohydrogenation in the rumen. Apparent transfer efficiency of eicosapentaenoic acid and docosahexaenoic acid from feed to milk is very low (1.9 to 3.3%), which is, to a large extent, related to their extensive biohydrogenation in the rumen. Therefore, feeding a rumen-protected supplement containing eicosapentaenoic acid and docosahexaenoic acid, can be used to bypass the rumen. Ruminant-derived foods also contain different types of conjugated linoleic acid isomers, which are intermediates of rumen biohydrogenation of linoleic acid (9c12c-18:2). The predominant isomer of conjugated linoleic acid is 9c11t, which has numerous health benefits in animal models. The concentration of conjugated linoleic acid in ruminant-derived food products can be significantly enhanced through animal diet modification. We conclude that most current functional food products from ruminants have potential for their health-supporting properties, and for this market to succeed, an evidence-based approach should be developed in humans.

Trans-11 Vaccenic Acid Dietary Supplementation Induces Hypolipidemic Effects in JCR:LA-cp Rats

Trans-11 vaccenic acid [VA; 18:1(n-9)] is a positional and geometric isomer of oleic acid and is the precursor to conjugated linoleic acid (CLA) in humans. Despite VA being the predominant trans monoene in ruminant-derived lipids, very little is known about its nutritional bioactivity, particularly in conditions of chronic metabolic disorders, including obesity, insulin resistance, and/or dyslipidemia. The aim of this study was to assess the potential of VA to improve dyslipidemia, insulin sensitivity, or inflammatory status in obese and insulin-resistant JCR:LA-cp rats. The obese rats and age-matched lean littermates were fed a control diet or a control diet supplemented with 1.5% (wt:wt) VA for a period of 3 wk. The incorporation of VA and subsequent conversion to CLA in triglyceride was measured in adipose tissue. Glucose and insulin metabolism were assessed via a conscious adapted meal tolerance test procedure. Plasma lipids as well as serum inflammatory cytokine concentrations were measured by commercially available assays. VA supplementation did not result in any observable adverse health effects in either lean or obese JCR:LA-cp rats. After 3 wk of feeding, body weight, food intake, and glucose/insulin metabolism did not differ between VA-supplemented and control groups. The incorporation of VA and CLA into adipose triglycerides in obese rats fed VA increased by 1.5-fold and 6.5-fold, respectively, compared with obese rats fed the control diet. The most striking effect was a 40% decrease (P < 0.05) in fasting triglyceride concentrations in VA-treated obese rats relative to obese controls. Serum Il-10 concentration was decreased by VA, regardless of genotype (P < 0.05). In conclusion, short-term dietary supplementation of 1.5% VA did not result in any detrimental metabolic effects in JCR:LA-cp rats. In contrast, dietary VA had substantial hypo-triglyceridemic effects, suggesting a new bioactivity of this fatty acid that is typically found in ruminant-derived food products.

Stearoyl CoA desaturase gene polymorphism in Italian cattle breeds

Stearoyl COA desaturase (SCD) is a rate-limiting enzyme in the biosynthesis of monounsaturated fatty acids. In cattle, a number of studies support the hypothesis that SCD gene regulation and polymorphism may affect fatty acid composition and fat quality in meat and milk. In ruminant-derived food products, SCD activity has been correlated to the content of conjugated linoleic acid (CLA), a mixture of geometrical and positional isomers of linoleic acid C18:2 having several positive effects on human health (i.e. anticarginogenic, antiatherogenic and immunomodulating effects).Aim of this study was to assess the polymorphism of 3 previously reported Single Nucleotide Polymorphisms (SNPs) in exon 5 of SCD gene in 12 cattle breeds raised in Italy, to evaluate the genetic variability and the genetic differences due to breed and/or selection purpose. Breeds sampled cover the whole geographic area of Italian peninsula and represent different selective purposes: 6 meat-purpose or meat-prevalence breeds (Piedmontese [n=27], Chianina [n=26], Romagnola [n=28], Marchigiana [n=30], Italian Limousine [n=22], Podolica [n=28]), 5 dairy-purpose or dairy-prevalence breeds (Italian Holstein [n=28], Italian Brown [n=26], Alpine Grey [n=18], Rendena [n=24], Cabannina [n=21]) and 1 dual-purpose breed (Italian Red Pied [n=25]).Genotyping, carried out using a competitive allele specific PCR system (KASPar) by an out-sourcing service (Kbiosciences, UK), confirmed the 3 SNPs being polymorphic in all breeds analysed. In particular, allele frequencies of the non-synonymous SNP T/C at position 10329 of the genomic sequence (GenBank accession no. AY241932), range from 0.34 in Italian Red Pied to 0.89 in Grey Alpine, showing a high variability of this polymorphism across Italian cattle. It is worth mentioning that the C allelic variant of this SNP has been associated to higher SCD activity and MUFA concentration in milk in Italian Holstein, and to higher level of MUFA percentage and lower melting point in intra-muscular fat in the Japanese Black meat breed. In the 12 breeds analysed 5 haplotypes has been reconstructed. The most frequent, ATC and GCT, are present in all the breeds studied. Interestingly, the GTC haplotype is present only in the Italian beef breed Chianina, Marchigiana, Romagnola, Podolica e Piedmontese, the ACT haplotype only in two dairy breeds Rendena and Italian Brown, and the ACC haplotype only in the Podolica breed with a low frequency. The correspondence analysis based on the genotypes at the 3 SNPs shows a clear separation between Italian beef cattle breeds and the other breeds considered. This may reflect a differential selective pressure on SCD polymorphisms or a different evolutionary history of this group of breeds.

Analysis of Variation in cis-9, trans-11 Conjugated Linoleic Acid (CLA) in Milk Fat of Dairy Cows

Conjugated linoleic acid (CLA) is a fatty acid with numerous putative health benefits and is a natural component of ruminant-derived food products. An intermediate in rumen biohydrogenation is cis-9, trans-11 CLA, the major CLA isomer in milk fat. However, the major source of cis-9, trans-11 CLA in milk is endogenous synthesis by Δ9-desaturase conversion of trans-11C18:1, another rumen biohydrogenation intermediate. The desaturase indices serve as a proxy for Δ9-desaturase activity and are calculated from the ratios of fatty acid pairs that represent product/substrate for this enzyme. This study analyzed individual animal variation in milk fat content of cis-9, trans-11 CLA and in desaturase indices in milk fat. Thirty lactating Holstein cows were allocated to one of three treatment groups: one received a standard total mixed ration, one received a diet that produced an elevated milk fat content of CLA, and a third treatment group was alternated between these diets at 3-wk intervals over the 12-wk study. There was a two- to threefold variation among individuals on the same diet for both milk fat content of CLA and desaturase indices in milk fat. This hierarchy was maintained to a large extent over the 12-wk study even in the variable treatment group that alternated between the two diets. Within the variable diet treatment, some animals consistently had a substantial response in milk fat content of CLA to dietary shifts, whereas other cows had little or no response. We conclude that while diet is a major determinant of the CLA content in milk fat, individual animal differences also have a substantial effect. The variation among individuals includes differences related to both rumen biohydrogenation and Δ9-desaturase activity in the mammary gland.

Cell signal mechanisms, conjugated linoleic acids (CLAs) and anti-tumorigenesis

Fats have been adversely implicated in the aetiology of many forms of cancer yet evidence is accumulating that certain types of fatty acids have anticancer properties. This is well documented for fish-oil fatty acids of the n-3 family. Recently, fatty acids found to occur naturally in ruminant-derived food products were found to have anticancer properties. These fatty acids were identified as conjugated linoleic acids (CLAs) derived from the parent linoleic acid by its partial hydrogenation by rumen bacteria. Studies with tumour-bearing animals have shown that consumption of CLAs particularly with regard to breast and prostate cancer is beneficial. Studies with cancer cells have also shown that these fatty acids can inhibit cell proliferation and induce cell death. However, little is known regarding the mechanisms of action of these CLAs. In particular, which cellular signal mechanisms are regulated by CLAs which can explain their anticancer properties. We have shown that CLAs specifically up-regulate cell signal systems at the level of gene expression (mRNA, protein) in human breast and prostate cancer cells which are responsible for the induction of apoptosis or programmed cell death. These findings support the anticancer effects of CLA found in animal models and indicate similar effects could occur in man.

The Importance of Source-Dependent Bioavailability in Determining the Transfer of Ingested Radionuclides to Ruminant-Derived Food Products

The transfer of radioactivity to the milk and meat of farm animals is likely be a major exposure pathway of human populations, following an environmental release of radioactivity. The importance of source-dependent bioavail ability in determining absorption from the ruminant gastrointestinal tract of the radiologically significant radionuclides (radiocesium, radiostrontium, radioiodine, and plutonium) is reviewed. The requirements for and suitability of in vitro methods of determining bioavailability for absorption of these radionuclides is also assessed. Radiocesium absorption varies over a 50-fold range, depending upon dietary source. Source-dependent bioavailability is therefore an important factor in determining the radiocesium contamination of ruminant-derived food products, and reliable in vitro techniques have been developed to rapidly determine its bioavailability. In contrast, under conditions of adequate calcium intake, the absorption of radiostrontium will not be greatly influenced by the dietary source. Results of in vitro extractions of radiostrontium could be misleading, as they indicate differences in bioavailability that are not observed in the animal. Absorption of radioiodine is complete and independent of source. There is currently a lack of data on plutonium absorption in ruminants. However, on the basis of the limited data available, in vitro incubations provide a measure of the relative bioavailabilities of plutonium from different sources. The applicability of the techniques reviewed to the study of other radionuclides and heavy metals is discussed.