Forage based diet as an alternative to a high concentrate diet for finishing young bulls - Effects on growth performance, greenhouse gas emissions and meat quality.

Two groups of 8 individually housed young crossbred-bulls, in the finishing period, were used to test the effect of a Total Mixed Ration diet with high forage content (54% DM), low starch content (14% DM), supplemented with sunflower seeds (10% DM) (HFS) on growth performance, carcass and meat quality, fatty acid profile and carbon footprint, with reference to a conventional concentrate-based (90% DM) (Control) diet. The experiment lasted 64 days before slaughter. During the experiment, feed intake was monitored daily and live weight every 14 days. Individual CH4 emissions were assessed at 16-days intervals, using a GreenFeed for Large Animal unit. Feed intake and feed conversion ratio were higher for HFS diet, but average daily weight gain and feeding costs were similar for the two diets. Dressing percentage was reduced with HFS diet. The HFS increased redness, yellowness and Chroma of subcutaneous fat, but did not compromise commercial value of the carcasses. Meat colour, shear force, or sensory parameters were not affected by diet. The HFS diet allowed a healthier FA profile, due to the higher proportions of 18:3n-3, t11-18:1 and c9,t11-18:2 and the lower proportion of t10-18:1. The HFS diet did not reduce the carbon footprint in the finishing period of young bulls, due to increased digestive CH4 emissions. The results of this experiment showed that the HFS diet can be an alternative to the conventional diets used in finishing young-bulls. Although it may result in a slight reduction in animal performance, it has a strong impact on reducing dependence on inputs from outside the farm.

Effects of partial substitution of grain by agroindustrial byproducts and sunflower seed supplementation in beef haylage-based finisher diets on growth, in vitro methane production and carcass and meat quality.

Thirty-two bulls were assigned to four total mixed biodiverse haylage-based diets to evaluate the effects of partial substitution of grains by agroindustrial byproducts, sunflower seeds (SS) supplementation and haylage level on growth, in vitro methane production and carcass and meat quality. Dietary treatments included a grain-based diet with 30% grain and haylage:concentrate ratio (H:C) of 60:40 (DM basis) (MCe); a by-product-based diet where 50% of the grain was substituted for by-products (H:C, 60:40) (MBp); a byproducts diet with 10% sunflower seed and 90% (DM) MBp (H:C, 54:46) (MBpSS); and a byproducts, SS diet with increased haylage (H:C, 67.5:32.5) (HBpSS). Dry matter intake and growth rate were lower in HBpSS, but feed conversion ratio was unaffected by diet. In vitro methane emissions were reduced by SS. Meat colour and shear force were similar among diets. Lipid oxidation in cooked meat was reduced and fatty acid composition was improved with SS. Biodiverse haylage-based diets may be a viable option for finishing bulls.

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.

Increasing the α-tocopherol content and lipid oxidative stability of meat through dietary Cistus ladanifer L. in lamb fed increasing levels of polyunsaturated fatty acid rich vegetable oils.

The aim of this study was to evaluate the effect of the dietary inclusion of Cistus ladanifer L. and vegetable oils on intramuscular fat composition, muscle antioxidant status and lipid oxidative stability, and explore the mechanism by which dietary Cistus ladanifer limits the lipid oxidation. Lambs were assigned 9 diets, corresponding to 3 levels of Cistus ladanifer (50, 100 and 200 g/kg DM) and 3 levels of oil (0, 40 and 80 g/kg DM). Oil supplementation increased highly peroxidizable fatty acid content and the peroxidizability index (P < .05). Muscle phenolic content, reducing ability and radical scavenging ability were not affected by Cistus ladanifer (P > .05). The highest level of Cistus ladanifer enhanced muscle resistance to lipid oxidation (P = .006) and increased α-tocopherol content (P = .005), reducing meat lipid oxidation over 7 days of storage (P < .001). Results showed that Cistus ladanifer has a protective effect against lipid oxidation through increasing α-tocopherol concentration in the muscle.

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.

Replacing cereals with dehydrated citrus pulp in a soybean oil supplemented diet increases vaccenic and rumenic acids in ewe milk.

This study evaluates the effect of the replacement of cereals by dried citrus pulp (DCP) in diets supplemented with 5% of soybean oil, on ewe milk yield and composition, including milk fatty acid (FA). Four Serra da Estrela multiparous ewes in the second month of lactation were used in a double 2×2 Latin square design. Ewes were individually penned and milked twice a day with an 8-h interval. Each experimental period included 14 d of diet adaptation followed by 5d of measurements and sampling. The 2 diets included on dry matter basis 450 g/kg of corn silage and 550 g/kg of either a soybean oil-supplemented concentrate meal containing barley and maize (cereal) or dried citrus pulp (DCP; citrus). Feed was offered ad libitum, considering 10% of orts, and intake was measured daily. Milk yield was higher and dry matter intake tended to be higher with the citrus diet. Milk composition and technological properties for cheese production were not affected by treatments, except for lactose, which was lower with the citrus diet. Replacement of cereals by DCP resulted in a 3-percentage-point decrease of both 18:0 and cis-9-18:1 that were mostly compensated by the 4.19- and 1.68-percentage-point increases of trans-11-18:1 and cis-9,trans-11-18:2, respectively. The intake of C18 FA tended to increase with the citrus diet compared with the cereal diet, but the apparent transfer of 18:2n-6 and of 18:3n-3 did not differ between diets. The milk output of C18 FA increased with the citrus compared with the cereal diet, mostly due to the increase of trans-11-18:1 and cis-9,trans-11-18:2 because the daily milk output of 18:0, trans-10-18:1, cis-9-18:1, 18:2n-6 and 18:3n-3 did not differ between diets. Replacing cereals with DCP in an oil-supplemented diet resulted in a selective increase of trans-11-18:1 and cis-9,trans-11-18:2 in milk, with no major effect on other biohydrogenation intermediates.