β-Carotene and lutein in forage and bovine adipose tissue in two tropical regions of Mexico

Using portable visible and near-infrared spectroscopy to authenticate beef from grass, barley, and corn-fed cattle

Meat product labels including information on livestock production systems are increasingly demanded, as consumers request total traceability of the products. The aim of this study was to explore the potential of visible and near-infrared spectroscopy (Vis-NIRS) to authenticate meat and fat from steers raised under different feeding systems (barley, corn, grass-fed). In total, spectra from 45 steers were collected (380-2,500 nm) on the subcutaneous fat and intact longissimus thoracis (LT) at 72 h postmortem and, after fabrication, on the frozen-thawed ground longissimus lumborum (LL). In subcutaneous fat samples, excellent results were obtained using partial least squares-discriminant analysis (PLS-DA) with the 100 % of the samples in external Test correctly classified (Vis, NIR or Vis-NIR regions); whereas linear-support vector machine (L-SVM) discriminated 75-100 % in Test (Vis-NIR range). In intact meat samples, PLS-DA segregated 100 % of the samples in Test (Vis-NIR region). A slightly lower percentage of meat samples were correctly classified by L-SVM using the NIR region (75-100 % in Train and Test). For ground meat, 100 % of correctly classified samples in Test was achieved using Vis, NIR or Vis-NIR spectral regions with PLS-DA and the Vis with L-SVM. Variable importance in projection (VIP) reported the influence of fat and meat pigments as well as fat, fatty acids, protein, and moisture absorption for the discriminant analyses. From the results obtained with the animals and diets used in this study, NIRS technology stands out as a reliable and green analytical tool to authenticate fat and meat from different livestock production systems.

Can botanically-diverse pastures positively impact the nutritional and antioxidant composition of ruminant meat? - Invited review

A desire for more sustainable pasture-based ruminant feeding systems has led to growing interest in utilising botanically-diverse pastures (BDP) over monoculture pastures. Research suggests that, from a human consumption viewpoint, grass-based ruminant feeding leads to more nutritionally desirable fatty acid (FA) and antioxidant concentrations in meat compared with concentrate feeding, which can affect meat quality. The FA, antioxidant and secondary metabolite content of plants differ, depending on species, maturity and seasonality, offering the potential through targeted feeding of BDP to produce meat with superior nutritional and antioxidant profiles. This review explores the effect, if any, that grazing ruminants on BDP has on the FA profile, fat-soluble vitamin, and antioxidant content of meat. The input-output relationship between forage and red meat constituents is complex and is likely affected by species diversity, forage consumption patterns and modulation of rumen fermentation processes. Further investigation is required to fully understand the effect that BDP may have on the composition and quality of ruminant meat.

Quantification of Chlorophyll and Carotene Pigments Content in Mountain Melick (Melica nutans L.) in Relation to Edaphic Variables

The aim of the study was to identify and compare the content of chlorophyll and carotene pigments in mountain melick plants (Melica nutans L.) growing in two forest habitats in the Zielonka Forest Landscape Park in the Greater Poland region, which differed in soil properties and moisture. Leaf blades from the middle level of Melica nutans generative shoots were used as analytical material to measure the content of chlorophyll a, chlorophyll b, β-carotene and total carotenoids. The average (±SD) content of chlorophyll a in the Melica nutans plants growing in the less fertile site (Location I) amounted to 6.67 ± 0.99 mg·g−1 DM. The average content of chlorophyll b in the same plants was 2.44 ± 0.39 mg·g−1 DM. The Melica nutans plants growing in the more fertile site (Location II) had a higher content of chlorophyll a, i.e., 7.76 ± 0.96 mg·g−1 DM, and lower content of chlorophyll b, i.e., 2.36 ± 0.26 mg·g−1 DM. The plants collected from both sites had similar content of β-carotene, i.e., 0.61 ± 0.11 mg·g−1 DM Location I and 0.62 ± 0.07 mg·g−1 DM Location II. The plants growing in the less fertile site (Location I) had significantly higher total carotene content than the plants in the more fertile site (Location II). The content of pigments in the Melica nutans plants was significantly differentiated by the meteorological conditions in the subsequent years of the research. In the first year of the research, the average content of all chlorophyll pigments in the plants was significantly higher than in the second drier year, regardless of the site.

Effect of β-carotene supplementation on the expression of lipid metabolism-related genes and the deposition of back fat in beef cattle

To evaluate the effects of β-carotene (βC) supplementation on lipid metabolism in the back fat of beef cattle, 120 continental crossbred (Simmental × local Luxi yellow cattle) steers were selected randomly from feedlots and allotted to four groups. Each steer was supplemented with 0, 600, 1200, or 1800 mg/day of βC for 90 days, and then received no βC for 60 days (depletion period). The βC levels significantly increased in steers supplemented with βC (P < 0.01), and then decreased to the control level by Day 150. Back fat thickness decreased slightly with increasing βC supplementation, and significantly differed among groups after supplementation ceased (P < 0.01 on Day 120, P < 0.05 on Day 150). Significant regression relationships between βC supplement level and both βC content in back fat tissue on Day 90 and back fat thickness on Days 90, 120, and 150 were established (P < 0.01). No significant differences in the dry matter intake or average daily gain were detected, but higher net meat percentages were observed in the 1200 and 1800 mg/day βC-supplemented groups compared with the control (P < 0.05). The mRNA expression of two fat synthesis-related genes, acetyl-CoA carboxylase and fatty acid synthase, were downregulated during the supplementation period, but upregulated during the next 60 days when the steers received no βC supplementation. In contrast, the expression of two fat hydrolysis-related genes, hormone-sensitive lipase and adipose triglyceride lipase, were upregulated during the supplementation period and downregulated in the subsequent 60 days. The results showed that βC supplementation suppresses back fat deposition in beef cattle by inhibiting fat synthesis and enhancing fat hydrolysis.

The etiology of oxidative stress in the various species of animals, a review

Oxidative stress is the consequence of an imbalance of pro-oxidants and antioxidants leading to cell damage and tissue injury. The exhaustion of antioxidant systems is one of the reasons for the occurrence of oxidative stress, which results in avalanche production of reactive oxygen species (ROS) or free radicals. High oxidative stress is common in organs and tissues with high metabolic and energy demands, including skeletal and heart muscle, liver and blood cells. Stress arises in animals in response to unavoidable or adverse environmental conditions. In the external environment, which affects the body of the cow, there are four main groups of stressors: physical, chemical, biological and psychological. Physical stressors include fluctuations in ambient temperature as well as mechanical injuries. High ambient temperature is one of the factors affecting the productivity of cows. Biological stressors are conditioned by errors and irregularities in habits. Both of these phenomena have an adverse impact on both the resistance of animals and fertility and are the etiological agent of oxidative stress. Various mechanisms may be responsible for metal-induced oxidative stress: direct or indirect generation of ROS, depletion of glutathione and inhibition of antioxidant enzymes are well known for all redox-active and redox-inactive metals.

Effects of feeding β-carotene on levels of β-carotene and vitamin A in blood and tissues of beef cattle and the effects on beef quality

The effects of feeding β-carotene (βC) on levels of βC and vitamin A (retinol) in blood and tissues, and on beef quality, were evaluated in 120 steers. Each steer received supplementary βC (at concentrations of 0, 600, 1200, or 1800 mg/day) for 90 days and then received no supplementary βC for 60 days. βC significantly increased in blood serum, liver, and subcutaneous and omental fat; linearly increased in the intestine and muscle; and remained unchanged in perirenal fat during supplementation. Differences between treatment groups were eliminated in subcutaneous and omental fat and in the liver by days 120 and 150, respectively, but remained significant at day 150 in blood. Retinol increased significantly in the liver and intestine during supplementation. Intramuscular fat content, meat color, and retinol in blood, muscle, or adipose tissues were not affected. Backfat thickness decreased slightly with increasing βC supplementation and significantly differed between groups during depletion.

Effect of 2,4-thiazolidinedione on limousin cattle growth and on muscle and adipose tissue metabolism

The main adipogenic transcription factor PPARγ possesses high affinity to 2,4-TZD, a member of the Thiazolidinedione family of insulin-sensitizing compounds used as adipogenic agents. We evaluated 2,4-TZD's effect on bovine growth and PPAR tissue expression. Seventeen Limousin bulls (18 month-old; 350 kg body weight (BW)) were assigned into 2 treatments: control and 2,4-TZD (8 mg/70 kg BW) and were fed until bulls reached 500 kg BW. They were weighed and their blood was sampled. DNA, RNA, and protein were determined in liver; skeletal muscle; subcutaneous (SC), omental, perirenal adipose tissues (AT) to determine protein synthesis rate and cellular size. Expression of PPAR mRNA was measured in liver and muscle (PPARα, -δ, and -γ) and SC adipose tissue (γ) by real-time PCR. No significant differences were found (P > 0.1) in weight gain, days on feed, and carcass quality. Muscle synthesis was greater in controls (P < 0.05); cell size was larger with 2,4-TZD (P < 0.05). PPARα, -δ, and -γ expressions with 2,4-TZD in liver were lower (P < 0.01) than in muscle. No differences were found for PPARγ mRNA expression in SCAT. The results suggest the potential use of 2,4-TZD in beef cattle diets, because it improves AT differentiation, liver, and muscle fatty acid oxidation that, therefore, might improve energy efficiency.

Digestion and absorption of carotenoids in sheep given fresh red clover

Digestion and absorption of carotenoids were studied in sheep given, twice daily, fresh red clover. Digestive fluxes were measured in six sheep cannulated in the rumen, duodenum and ileum using the double marker technique. Another five sheep were fitted with catheters allowing nutrient net flux measurements across the portal-drained viscera. Carotenoids in the red clover consisted of lutein (136 μg/g dry matter (DM)), epilutein (40 μg/g DM),trans-β-carotene (16 μg/g DM) and 13-cis-β-carotene (13 μg/g DM). Intake was 174, 52, 21 and 17 mg/day, and faecal excretion was 181, 25, 50 and 41 mg/day, for lutein, epilutein,trans- and 13-cis-β-carotene respectively, indicating net production of β-carotene in the digestive tract. The difference between duodenum and intake was positive for all carotenoids (30, 4, 43 and 37 g for lutein, epilutein,trans-β-carotene and 13-cis-β-carotene, respectively) suggesting net production and/or release of carotenes and xanthophylls by rumen microbes. Apparent digestibility in the small and large intestines was 0·18 and −0·05 for lutein, 0·30 and 0·29 for epilutein, 0·39 and 0·26 fortrans-β-carotene, 0·53 and 0·21 for 13-cis-β-carotene. Only lutein and epilutein were recovered in arterial plasma, at a concentration of 14·3 and 10·8 μg/l, respectively. Their portal net appearance was not different from 0, suggesting that absorption occurred mainly via the lymphatic system.

Variations in Carotenoids, Fat-Soluble Micronutrients, and Color in Cows’ Plasma and Milk Following Changes in Forage and Feeding Level

The main aim of this work was to assess factors affecting the secretion of carotenoids in cows' milk. Our objectives were 1) to determine the kinetics of the decrease in carotenoids in plasma, milk, and adipose tissues following a switch from a high- to a low- carotenoid diet; and 2) to specify whether, during lipomobilization, the restitution of these compounds stored in the adipose tissues is sufficient to modify their secretion in milk. During the preexperimental period, 32 cows in midlactation were fed a grass silage-based diet, and were then assigned to 4 groups; 2 groups were maintained on the grass silage diet and 2 were switched to a late hay diet. For each forage diet, one group was fed according to net energy for lactation and nitrogen requirements, and the other was submitted to an energetic underfeeding, with similar forage and carotenoid intake between groups. Variations in concentration of carotenoids and color index (CI) of plasma and milk were monitored over 8 wk. Other components of nutritional interest; i.e., vitamin E (VE), vitamin A, and fatty acids, were also measured. The switch from grass silage to hay diet induced a rapid decrease in concentration of betal-carotene (BC) and VE and in the CI of plasma and milk during the first 2 wk. Pools of BC in adipose tissues also decreased by 40%. Concentrations of BC at the end of the experiment for silage and hay groups were 5.10 and 1.71 microg/mL in plasma and 0.17 and 0.07 microg/mL in milk, respectively. The energetic underfeeding did not affect BC concentration in plasma and induced a small increase in milk BC concentration, related to a decreased milk yield. In the silage group, the energetic underfeeding after 3 to 4 wk induced a decrease in CI and VE of plasma, but not of milk. The fatty acid profile in milk was modified by the change from grass silage to hay diet (C10 to C14 and linoleic acid increased; stearic and linolenic acid percentages decreased) and by underfeeding (oleic, vaccenic, and rumenic acid percentages increased). This study shows that BC and VE levels persist in midlactation cows' plasma and milk for about 2 wk. The results could not confirm a release of BC by bovine adipose tissue, but the level of underfeeding was moderate in this trial. The concentration of BC explained 58 and 40% of variation in CI of plasma and milk, respectively. These CI appear to be valuable tools for diet traceability (i.e., silage vs. hay).