Plasma transport and mammary uptake of trans fatty acids in dairy cows

In this thesis, aspects of metabolism of lipids in dairy cows were studied, particularly 18:1 trans fatty acid (tFA) concentrations in plasma and lipoprotein fractions, and transportation of FA in epithelial mammary gland cell cultures. Two in vivo studies were conducted to elucidate which lipoprotein fractions were involved in bovine plasma transport of tFA by infusing oils that induced different plasma tFA profiles. Fatty acid profiles of plasma and lipoprotein fractions [high (HDL), low (LDL), and very low density (VLDL) lipoprotein fractions] were analysed. Results showed that VLDL fraction was the main transport mechanism of tFA in plasma and was more responsive to supply of tFA. MAC-T cell cultures were used to study specific aspects of lipid uptake without interference from the cow’s digestive system and general metabolism. Treatments consisted of adding long-chain FA solutions to lactogenic medium at varying concentrations. After incubation, cystosolic triacylglycerol (TAG), protein and DNA contents were determined. Results demonstrated that cytosolic TAG accumulation is stimulated by addition of long-chain FA, which affects FA profile of cytosolic free FA. Overall, results from this thesis enhance knowledge on plasma transport and mammary uptake of 18:1 tFA in dairy cows. The information strengthens understanding of some aspects of milk fat synthesis and metabolism of FA in dairy cows fed with different sources of tFA. Findings from this thesis are important because saturated FA and tFA in milk fat have caused concern among human health researchers and more recently milk fat has gained appreciation as a functional food due to the health-promoting potential of some FA (vaccenic and conjugated linoleic acids) found specifically in ruminant-derived products

Plasma transport and mammary uptake of trans fatty acids in dairy cows

In this thesis, aspects of metabolism of lipids in dairy cows were studied, particularly 18:1 trans fatty acid (tFA) concentrations in plasma and lipoprotein fractions, and transportation of FA in epithelial mammary gland cell cultures. Two in vivo studies were conducted to elucidate which lipoprotein fractions were involved in bovine plasma transport of tFA by infusing oils that induced different plasma tFA profiles. Fatty acid profiles of plasma and lipoprotein fractions [high (HDL), low (LDL), and very low density (VLDL) lipoprotein fractions] were analysed. Results showed that VLDL fraction was the main transport mechanism of tFA in plasma and was more responsive to supply of tFA. MAC-T cell cultures were used to study specific aspects of lipid uptake without interference from the cow’s digestive system and general metabolism. Treatments consisted of adding long-chain FA solutions to lactogenic medium at varying concentrations. After incubation, cystosolic triacylglycerol (TAG), protein and DNA contents were determined. Results demonstrated that cytosolic TAG accumulation is stimulated by addition of long-chain FA, which affects FA profile of cytosolic free FA. Overall, results from this thesis enhance knowledge on plasma transport and mammary uptake of 18:1 tFA in dairy cows. The information strengthens understanding of some aspects of milk fat synthesis and metabolism of FA in dairy cows fed with different sources of tFA. Findings from this thesis are important because saturated FA and tFA in milk fat have caused concern among human health researchers and more recently milk fat has gained appreciation as a functional food due to the health-promoting potential of some FA (vaccenic and conjugated linoleic acids) found specifically in ruminant-derived products

Physical quality of different industrial versus non-industrial eggs obtained from groceries and markets in southern Chile

The aim of this study was to determine external and internal quality parameters of industrial (cages and cage-free) and family farms eggs that are normally available at groceries in developing countries such as Chile. Two experiments were performed to evaluate 1) quality differences between family farms and industrial eggs and 2) to determine quality differences between brown shell eggs from different industrial cage and cage-free systems. Experiment 1 consisted of five groups where three of them were industrial eggs: i) cage white shell eggs, ii) cage brown shell eggs, iii) brown shell cage-free eggs; and two of them were non-industrial: iv) family farm brown shell eggs and v) family farm blue shell eggs. Experiment 2 had four groups, all brown-shell types of eggs were used: i) cage brown eggs, ii) cage-free from aviary eggs, iii) southern free-range eggs and iv) central free-range eggs. In both Experiments, egg weight, egg length, egg width, egg shape index, Haugh units, albumen ratio, egg yolk, yolk weight and albumen weight, blood and meat spots were determined. In Experiment 1, brown and blue-shelled family farm eggs were equal in terms of external and internal quality, except for blood spots, with brown eggs having more incidence. In Experiment 2, free-range eggs presented more intense yolk colors compared to those from battery and cages. In both experiments, free-range eggs presented the darker yolk color. It can be concluded that brown and blue-shelled family farm eggs are equal in terms of external and internal quality, except for blood spots, with brown eggs having more incidence. In addition, free-range eggs from the southern part of the country presented better shell quality, whereas free-range eggs presented more intense yolk colors, while those of battery

Nutrigenomic effect of saturated and unsaturated long chain fatty acids on lipid-related genes in goat mammary epithelial cells:What is the role of PPARγ?

A prior study in bovine mammary (MACT) cells indicated that long-chain fatty acids (LCFA) C16:0 and C18:0, but not unsaturated LCFA, control transcription of milk fat-related genes partly via the activation of peroxisome proliferator-activated receptor gamma (PPARγ). However, in that study, the activation of PPARγ by LCFA was not demonstrated but only inferred. Prior data support a lower response of PPARγ to agonists in goat mammary cells compared to bovine mammary cells. The present study aimed to examine the hypothesis that LCFA alter the mRNA abundance of lipogenic genes in goat mammary epithelial cells (GMEC) at least in part via PPARγ. Triplicate cultures of GMEC were treated with a PPARγ agonist (rosiglitazone), a PPARγ inhibitor (GW9662), several LCFA (C16:0, C18:0, t10,c12-CLA, DHA, and EPA), or a combination of GW9662 with each LCFA. Transcription of 28 genes involved in milk fat synthesis was measured using RT-qPCR. The data indicated that a few measured genes were targets of PPARγ in GMEC (SCD1, FASN, and NR1H3) while more genes required a basal activation of PPARγ to be transcribed (e.g., LPIN1, FABP3, LPL, and PPARG). Among the tested LCFA, C16:0 had the strongest effect on upregulating transcription of measured genes followed by C18:0; however, for the latter most of the effect was via the activation of PPARγ. Unsaturated LCFA downregulated transcription of measured genes, with a lesser effect by t10,c12-CLA and a stronger effect by DHA and EPA; however, a basal activation of PPARγ was essential for the effect of t10,c12-CLA while the activation of PPARγ blocked the effect of DHA. The transcriptomic effect of EPA was independent from the activation of PPARγ. Data from the present study suggest that saturated LCFA, especially C18:0, can modulate milk fat synthesis partly via PPARγ in goats. The nutrigenomic effect of C16:0 is not via PPARγ but likely via unknown transcription factor(s) while PPARγ plays an indirect role on the nutrigenomic effect of polyunsaturated LCFA (PUFA) on milk fat related genes, particularly for CLA (permitting effect) and DHA (blocking effect)

Trends and drivers of change of pastoral beef production systems in a mediterranean-temperate climate zone of chile

The present study used surveys of the cattle sector over the period of 2009–2015 to develop a typology of cattle farms to evaluate their evolution over time and to identify variables that may be associated with systems’ adaptive changes and continuance. Four groups of farms were defined using multivariate analyses as follows: Group I are small calf-cow operations using non-specialized beef breeds; Group II is similar to Group I but employs specialized beef breeds; Group III is dedicated to finishing cattle, and Group IV are larger farms (>1000 animals) with a complete cycle of breeding and fattening. In general, beef cattle production in the temperate—Mediterranean Southern Zone of Chile is declining in response to the opening up of the economy that allows for ample imports, the high opportunity cost of land, and recurrent droughts associated with climate change. Current policies and regulations have modified farms’ businesses models depending on their ease of access to markets, farm size and financial capacity. The defined groups require different development paths and strategies. Sustainable intensification is an alternative strategy for farms in Group I and II, particularly if they were to contract the finishing stage of their cattle with Group III farms. In contrast, it is suggested that Group IV farms concentrate on pastoral production using low external inputs to enhance the production of “natural” beef for high-value niche markets, with positive externalities

Characterisation of dairy female calf management practices in southern Chile

The objective of this study was to characterise husbandry and technical-productive practices at the calf rearing stage in dairy farms in Los Lagos Region, southern Chile. A face-to-face survey was applied to 22 dairy farms in Los Lagos Region in 2017. All farms performed artificial calf rearing under either of two systems: total barn confinement (48%) or a mixed system that considers the first stage with confinement and the second stage in open-air paddocks (52%). More than half (52%) of the farms supplied fresh colostrum to the calf from its dam and the rest of the farms used bottle or oesophageal tube. Only 30% of the farms evaluated colostrum quality using colostrometer (densimeter) or refractometer. After the colostrum supply, milk replacers, waste milk, or a mixture of both were used for calf feeding. Most of the farms (66.7%) did not have automated milk-feeding systems and used bottles (88.9%) and buckets (11.1%) instead. On average, calves were handled by 1.5 caretakers (SD: 0.63) of which 63.4% (SD: 40.2) were men. The average age for caretakers was 43.9 years (SD: 12.7), with 23.8% being less than 35 years old. Overall, results from this study can be used to identify key managements that could improve calves’ rearing productive traits

Oxidative quality and color variation during refrigeration (4 °C) of rainbow trout fillets marinated with different natural antioxidants from oregano, quillaia and rosemary

The study aimed at determining the antioxidant effect of natural extracts on the oxidative quality and color variation of rainbow trout fillets during storage at 4 °C. The fillets were marinated and samples from the belly flap area and Norwegian quality cuts were used for lipid oxidation determination while the dorsal region was used for color measurements. The fillets were marinated with the different treatments: 470 mg l-1 of oregano extract, 6.84 ml l-1 of quillaia extract, 7.2 ml l-1 of rosemary extract and 2 ml l-1 of a synthetic antioxidant. Maximum TBARS (Thiobarbituric acid reactive substances) values of belly flap and Norwegian quality cuts occurred at five and six days of storage, respectively. The susceptibility of treatments to lipid oxidation in decreasing order was: control>quillaia>oregano>rosemary>synthetic antioxidant. An increase in lightness (L*) and redness (a*) were observed for rosemary and quillaia extracts when compared to control samples. Marinates with natural antioxidants may be an alternative for extending shelf-life of trout fillets at least during the first six days of storage at 4 °C

Rangeland grazing management in argentine Patagonia

Stocking rate adjustment in grazing management is recommended as a management tool to sustain productivity and improve soil health of permanent grassland ecosystems. The aim of this project was to assess the effect of stocking rates under continuous grazing or simple levels of rotational grazing systems on the local environment, when using a moderate or high grazing intensity in the Argentine Patagonia. The parameters investigated were: 1) soil water infiltration and water retention capacity, 2) soil organic matter, N, erosion, and respiration and 3) Plant composition profiles, aboveground net primary production (ANPP), biomass above- and below- ground, physical plant characteristics, and species diversity. In the humid Magellanic grass steppe static rotational grazing was found to increase soil water infiltration rates, N, proportions of forbs and shrubs, root/aerial plant ratio, number of plant species, and proportion of dead plant. Continuous grazing had a greater ANPP, proportion of bare soil, and grasses and graminoids. Under silvopastoral Andean vegetation conditions, rotational grazing resulted in increased root biomass, root/aerial plant ratio, and proportion of forbs compared to continuous grazing, which was found to increase soil organic matter, N, plant length, root depth, aerial plant biomass, soil respiration, proportion of bare soil and dead plants compared to rotational grazing. Intensive grazing negatively influenced soil water, soil and vegetation parameters. The results indicated that adjustment of stocking rate or rotational grazing has a potential to store more biomass than continuous grazing.EEA Santa CruzFil: Bjerring, Anna Trier. University of Copenhagen. Faculty of Health and Medical Sciences. Department of Veterinary and Animal Sciences; DinamarcaFil: Peri, Pablo Luis. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Santa Cruz; Argentina.Fil: Peri, Pablo Luis. Universidad Nacional de la Patagonia Austral; Argentina.Fil: Peri, Pablo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: Christiansen, Rodolfo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Santa Cruz; Argentina.Fil: Christiansen, Rodolfo. Universidad Nacional de la Patagonia Austral; Argentina.Fil: Vargas-Bello-Pérez, Einar. University of Copenhagen. Faculty of Health and Medical Sciences. Department of Veterinary and Animal Sciences; DinamarcaFil: Hansen, Hanne Helene. University of Copenhagen. Faculty of Health and Medical Sciences. Department of Veterinary and Animal Sciences; Dinamarc

Interplay between productive traits, the social rank, and the cow’s stability in the order of entrance to the milking parlour

The aim of this study was to investigate whether social rank (SR) and stability in the order of entrance to the milking parlour are associated with production traits. The study was conducted on a dairy farm where cows (n = 215) were managed in three groups according to lactation stage (group 1: 78 cows, 0–100 days in milk (DIM); group 2: 65 cows, 101–200 DIM and group 3: 72 cows, >200 DIM). SR was calculated from observations made from agonistic behaviour performed at the water troughs and feed bunks of each pen (n = 3). The animals were classified into three levels of dominance based on at least five clear interactions, resulting in: 61 dominant, 75 intermediate and 69 subordinate cows based on SR. Stability in the order of entry was estimated as the standard deviation of the entry position. SR was weakly correlated with milk yield, urea and protein content in milk. The results showed that stable cows had higher milk production and entered the milking parlour after the non-stable animals. Stability in the order of entry to the milking parlour was not affected by SR. Overall, the use of milking facilities appears to be associated with production traits rather than SR