Gradually increasing vitamin E dose allow to increase dietary polyunsaturation level while maintaining the oxidation status of lipids and proteins in chicken breast muscle

Feeding broilers diets high in n-3 long-chain polyunsaturated fatty acids (n-3 PUFA) increases their incorporation into the meat but it may compromises meat quality due to oxidation of lipids and protein. Increased dietary vitamin E (vE) level downregulate this process, but its excessive level might exceed the physiological requirements for the maintenance of redox balance. This study investigated the sensory characteristics and oxidative status of meat from chickens fed diets supplemented with fish oil (FO) with or without gradually increasing doses of vE. The meat samples were obtained from total of 27 female broilers of Ross 308 strain (9 birds per each of 3 dietary treatment), which were housed according to the standard management practice for commercial chicken houses over a period of 36 days. Chickens were fed diets contained 80 g/kg of supplemental fat, but the diets differed in fat composition; control diet (80 g/kg diet beef tallow as supplemental fat and a basal vE dose; 40 IU of dl-α-tocopheryl acetate; diet containing mixture of FO and beef tallow as supplemental fat (50:30 w/w g/kg diet) and a basal vE dose (E1), or diet (E2) as diet E1 but with gradually increasing vE dose (120/240 IU/kg diet fed between days 8-21 and days 22-36, respectively). The highest sensory quality and the lowest oxidative status of meat was found in the control chickens. FO decreased the sensory quality of the meat and increased lipid oxidation as well it had an impact on the lipid profile in muscle tissue (PUFA, n-3 ALA, EPA, DHA). Administration of a graded vE dose increased the sensory quality of the meat and did not limit lipid oxidation but maintained protein oxidation balance.

Feeding Grazing Dairy Cows With Different Energy Sources on Recovery of Human-Edible Nutrients in Milk and Environmental Impact

The use of grazing systems for milk production is widely used globally because it is a lower-cost feeding system. However, under tropical conditions, the energy content of pastures became is a limitation to improve animal performance and efficiency while reducing the environmental impact. The objective of our study was to evaluate the impact of supplying different dietary sources of energy to lactating dairy cows grazing tropical pastures on the recovery of human-edible (HE) nutrients in milk and the environmental impact. Two experiments were conducted simultaneously. In experiment 1, forty early lactating dairy cows were used in a randomized block design. In experiment 2, four late-lactating rumen-cannulated dairy cows were used in a 4 × 4 Latin Square design. All cows had free access to pasture and treatments were applied individually as a concentrate supplement. Treatments were flint corn grain-processing method either as fine ground (FGC) or steam-flaked (SFC) associated with Ca salts of palm fatty acids supplementation either not supplemented (CON) or supplemented (CSPO). We observed that feeding cows with SFC markedly reduced urinary nitrogen excretion by 43%, and improved milk nitrogen efficiency by 17% when compared with FGC. Additionally, we also observed that feeding supplemental fat improved milk nitrogen efficiency by 17% compared with cows receiving CON diets. A tendency for decreased methane (CH4) per unit of milk (−31%), CH4 per unit of milk energy output (−29%), and CH4 per unit of milk protein output (−31%) was observed when CSPO was fed compared with CON. Additionally, SFC diets increased HE recovery of indispensable amino acids by 7–9% when compared with FGC diets, whereas feeding supplemental fat improved HE recovery of indispensable amino acids by 17–19% compared with CON. Altogether, this study increased our understanding of how manipulating energy sources in the dairy cow diet under tropical grazing conditions can benefit HE nutrient recovery and reduce nutrient excretion.

PSVII-19 Transcriptomic analysis of the liver of laying hens fed diets containing supplemental fat at early laying stages

Feeding diets containing supplemental fat to laying hens is reported to ameliorate pathogenesis of fatty liver hemorrhagic syndrome (FLHS). However, molecular mechanisms for this positive effect have not been investigated. Thus, we conducted a transcriptomic analysis of the liver of laying hens fed diets containing supplemental fat at early laying stages. Two dietary treatments included basal diets with no supplemental fat and basal diets supplemented with 3.0% tallow. A total of 256 18-week-old Hy-line Brown laying hens were allotted to 1 of 2 treatments. Diets were fed to hens for 12 weeks. At the end of the experiment (30 weeks of age), 5 hens with similar BW per treatment were euthanized to collect liver tissues. The cDNA libraries were constructed with extracted RNA from the liver tissues, and sequenced using the Illumina Nextseq 500 sequencer. Genes with False Discovery Rate (FDR) < 0.05 were defined as differentially expressed genes (DEGs). Results indicated that a total of 951 DEGs were identified, with 483 being up-regulated and 468 being down-regulated in the liver of hens fed diets containing 3.0% tallow. The KEGG analysis revealed that the DEGs belong to several biological pathways such as cellular signaling pathways, carbon metabolism, glycolysis, gluconeogenesis, TCA cycle, amino acid metabolism, drug metabolism, and glycerophospholipid metabolism. Especially for fatty acid metabolism, the DEGs associated with fatty acid degradation (ECI2, ACSL1, HADHA, EHHADH, ACOX1, CPT1) were up-regulated, whereas those related to fatty acid synthesis (ACACA, ACSL5, FASN) were down-regulated in the liver of hens fed diets containing 3.0% tallow, which indicates that supplemental fat in diets may increase fat oxidation but decrease fat synthesis in the liver. These results provide the molecular insights for hepatic lipid metabolisms by feeding diets containing supplemental fat to laying hens at early laying stages.

Comparative effects of ‘solid’-fat sources as a substitute for yellow grease on digestion of diets for feedlot cattle

Five cannulated Holstein steers fed a steam-flaked corn-based growing diet containing 40% of alfalfa hay were used in a 5 × 5 Latin square design to examine the effect of ‘solid’ supplemental fats as a substitute for yellow grease (YG) on the extent and site of digestion. Treatments were (% of diet DM) as follows: (1) no supplemental fat; (2) 5% YG; (3) 5.88% calcium soaps (ML); (4) 5% flaked palmitic acid (RP10); and (5) 5% hydrogenated palm fatty acid distillate (HPFAD). Supplemental fats replaced the corn in the control diet. Supplemental fat decreased (P < 0.01) ruminal and total-tract digestion of organic matter and tended to decrease (P = 0.06) ruminal digestion of neutral detergent fibre, with no effects on ruminal digestion of feed N, microbial N efficiency, or total-tract digestion of N and neutral detergent fibre. With the exception of RP10, fat supplementation decreased (P < 0.03) postruminal digestion of C18:0. Compared with the original C16:0:C18:0 ratio of solid fats, the C16:0:C18:0 ratio of fatty acids (FAs) entering the small intestine markedly decreased for all solid-fat treatments. Ruminal biohydrogenation of YG and ML were 73% and 49% respectively. On the basis of FA intake, postruminal FA digestion of YG, ML, RP10 and HPFAD was 0.97, 0.94, 0.92 and 0.80 of expected respectively. This experiment confirmed that postruminal digestion of total FAs of conventional supplemental yellow grease is a predictable function of total FA intake per unit of bodyweight. However, in the case sources of the solids fats, this relationship (FA intake and postruminal digestion of FAs) was less consistent. This may be due to their physical and chemical nature (saturatedFA:unsaturated FA ratio). On the basis of the nutrient digestion and postruminal FA digestibility observed in the present experiment, solid supplemental fats do not afford appreciable advantages over conventional YG when supplemented in growing diets (forage level ~400 g/kg diet DM) for feedlot steers.