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Dietary resistant starch (RS) may have prebiotic properties but its effects on fermentation and the microbial population are inconsistent. This meta-analysis aimed to quantify the relationship between RS type 2 (RS2) and intestinal short-chain fatty acids (SCFA) and pH as well as certain key bacterial taxa for intestinal health in pigs. From the 24 included articles with sufficient information about the animal, and dietary and physiological measurements published between 2000 and 2017, individual sub-data sets for fermentation metabolites, pH, bacterial abundances and apparent total tract digestibility were built and used to parameterize prediction models on the effect of RS2, accounting for inter- and intra-study variability. In addition, the effect of pig's BW at the start of the experiment and duration of the experimental period on response variables were also evaluated using backward elimination analysis. Dietary RS levels ranged from 0% to 78.0% RS, with median and mean RS levels of 28.8% and 23.0%, respectively. Negative relationships could be established between dietary RS and pH in the large intestine (P <0.05), with a stronger effect in the mid and distal colon, and feces (R 2=0.64 to 0.81; P <0.001). A dietary level of 15% RS would lower the pH in the proximal, mid-, distal colon and feces by 0.2, 0.6, 0.4 and 0.6 units, respectively. Increasing RS levels, however, did not affect SCFA concentrations in the hindgut, but enhanced the molar proportion of propionate in mid-colon and reduced those of acetate in mid-colon and of butyrate in mid- and distal colon (R 2=0.46 to 0.52; P <0.05). Backward elimination indicated an age-related decrease in mid-colonic propionate proportion and increase in mid- and distal colonic butyrate proportion (P <0.05), thereby modulating RS2 effects. In feces, increasing RS levels promoted fecal lactobacilli (R 2=0.46; P <0.01) and bifidobacteria (R 2=0.57; P <0.01), whereby the slope showed the need for a minimal RS level of 10% for a 0.5 log unit-increase in their abundance. Best-fit equations further supported that a longer experimental period increased fecal lactobacilli but decreased fecal bifidobacteria (P <0.05). In conclusion, dietary RS2 seems to effectively decrease digesta pH throughout the large intestine and increase lactic acid-producing bacteria in feces of pigs which may limit the growth of opportunistic pathogens in the hindgut. To achieve these physiologically relevant changes, dietary RS should surpass 10% to 15%. [ABSTRACT FROM AUTHOR]

Meat from lambs finished with high-starch diets often contains low concentration of vaccenic (t11-18:1) and rumenic (c9,t11-18:2) acids and high concentration of t10-18:1. We hypothesized that replacing cereals by dehydrated citrus pulp (DCP) and the inclusion of tanniferous feed sources in oil supplemented diets might reduce the accumulation of t10-18:1 and increase the t11-18:1 and c9,t11-18:2 in lamb meat, without affecting the productive performance. In total, 32 lambs were assigned to four diets which combine two factors: basal diet (BD) (cereals v. DCP) and Cistus ladanifer (CL) (0 v. 150 g/kg dry matter). Feed intake, average daily weight gain and carcass traits were not affected by treatments, except for dressing percentage that was reduced with DCP (P=0.046). Both DCP and C. ladanifer reduced tenderness and juiciness of meat, and C. ladanifer also reduced (P<0.001) meat overall acceptability. Intramuscular fat and the concentration of saturated and polyunsaturated fatty acids (FA) were not affected (P>0.05) by diets. However, DCP increased the proportions of odd-chain FA (P=0.005) and several minor biohydrogenation (BH) intermediates in meat lipids. C. ladanifer had few effects on meat FA profile. The proportions of t11-18:1 and c9,t11-18:2 were high in all diets (5.4% and 1.5% of total FA, respectively) and were not influenced by the treatments. Basal diet and CL showed some significant interactions concerning FA composition of intramuscular fat. In diets without C. ladanifer, replacement of cereals by DCP increased the 18:0 (P<0.05) and decreased t10,c12-18:2 (P<0.05), t10-18:1 (P<0.10) and t10-/t11-18:1 ratio (P<0.10) with a large reduction of the individual variation for t10-18:1 and of t10-/t11-18:1 ratio. Combined with cereals, C. ladanifer increased 18:0 and reduced the BH intermediates in meat. Replacement of cereals by DCP seems to promote a more predictable FA profile in lamb meat, reducing the risk of t10-shifted BH pathways in the rumen. [ABSTRACT FROM PUBLISHER]

The present study aims to assess the effects of pig’s genotype (lean v. fatty) and dietary protein level (control v. reduced) on intramuscular fat (IMF) content, fatty acid composition and fibre profile of psoas major, a representative red muscle in pig’s carcass scarcely studied relative to white longissimus lumborum. The experiment was conducted on 40 intact male pigs (20 Alentejana purebred and 20 Large White×Landrace×Pietrain crossbred) from 60 to 93 kg of live weight. Pigs were divided and allocated to four dietary groups: control protein diet equilibrated for lysine (17.5% of CP and 0.7% of lysine) and reduced protein diet (RPD) not equilibrated for lysine (13.1% of crude protein and 0.4% of lysine) within a 2×2 factorial arrangement (two genotypes and two diets). Alentejana purebred had higher IMF content (15.7%) and monounsaturated fatty acids (MUFA) (8.9%), whereas crossbred pigs had higher PM weight (46.3%) and polyunsaturated fatty acids (PUFA) (20.1%). The genotype also affected colour with higher lightness (15.1%) and yellowness (33.8%) and lower redness (9.9%) scores in crossbred pigs. In line with this, fatty pigs displayed more oxidative fibres (29.5%), whilst lean pigs had more glycolytic (54.4%). Relative to fatty acids, RPD increased MUFA (5.2%) and SFA (3.2%) but decreased PUFA (14.8%). Ultimately, RPD increased IMF content (15.7%) in the red muscle under study, with no impact on glycolytic to oxidative fibre type transformation. [ABSTRACT FROM PUBLISHER]

The production of pork with moderate amounts of intramuscular fat (IMF) without an increase in subcutaneous fat is highly desirable for the meat industry. Several studies indicate that dietary protein reduction during the growing–finishing period of pigs enhances IMF content, but its consequence on carcass fat deposition is still contradictory. In this study, we hypothesized that the effects of reduced protein diets (RPD), corrected or not with the limiting amino acid lysine, on subcutaneous fat deposition from pigs with distinct genotypes are mediated by adipose membranes biophysical properties. In total, 36 crossbred (Large White×Landrace×Pietrain – a lean genotype) and purebred (Alentejana breed – a fatty genotype) male pigs were randomly assigned to the control group, the RPD group or the reduced protein diet equilibrated for lysine (RPDL) group, allowing a 2×3 factorial arrangement (n=6). Backfat thickness and total fatty acid content were higher in Alentejana relative to crossbred pigs. Although dietary treatments did not change backfat thickness, RPD and RPDL increased total fatty acids content of subcutaneous fat. In order to understand this effect, adipose tissue membranes isolated from pig’s subcutaneous fat were assayed for glycerol permeability and fluidity, using 1,6-diphenyl-1,3,5-hexatriene (DPH) and 1-(4-(trimethylamino)-phenyl)-6-phenyl-1,3,5-hexatriene (TMA-DPH) probes. The glycerol transport across adipose membranes was not mediated by aquaglyceroporins and remained unchanged across dietary groups. Regardless of lysine correction, RPD increased membrane fluidity at the hydrocarbon region (lower DPH fluorescence anisotropy) in both genotypes of pigs. This result was associated with a lower ratio between oleic acid and linoleic acid on membrane’s fatty acid composition. Adipose membrane’s cholesterol content was independent from genotype and diet. Taken together, the present study shows that dietary protein reduction is successful in maintaining backfat thickness, although a negative side effect was observed on total fatty acids in subcutaneous fat, which may be due to changes in the fluidity of adipose membranes. [ABSTRACT FROM PUBLISHER]

The traditional beef production in the South of Portugal is based on a discontinuous growth (DG) system that requires lower external inputs and could enhance meat quality and financial returns to cattle producers. This system allows farmers to take advantage of the bull’s compensatory growth when the pasture is abundant and finishes the cattle on concentrates for 2 to 3 months before slaughter. The fast gain rate before slaughter could be a valuable strategy to improve tenderness and to reduce its inconsistency in beef production. Therefore, the aim of this study was to evaluate the effects of production system (continuous growth (CG) v. DG) on longissimus thoracis muscle properties from Alentejana bulls. In total, 40 Alentejana male calves were allocated to two distinct feeding regimes: in the CG system, animals were fed concentrate plus hay and slaughtered at 18 months of age, whereas in the DG system, animals were fed on hay until 15 months of age and then fed the same diet provided to the CG group until 24 months of age. The DG system had a positive impact on meat tenderness (P<0.001) and global acceptability (P<0.001). DG bulls had greater fibre cross-sectional area (CSA) of glycolytic fibres (P<0.05) and relative area of the muscle (RA) occupied by type IIX fibres (P<0.01) and greater levels of α-actinin (P<0.05) and myosin light chain 2 (P<0.01) proteins, and pH24h (P<0.01) than CG bulls. The latter had greater CSA of type I (P<0.05) and type IIA (P<0.01) and greater RA of type IIA (P<0.05) and oxidative (P<0.05) than CG bulls. The compensatory growth production system had a positive impact on meat tenderness and global acceptability, overcoming the negative effects of slaughter of the bulls at a later age. The DG beef system could be a worthwhile strategy of beef production in Mediterranean areas due to the low-quality pasture in summer. [ABSTRACT FROM PUBLISHER]

The effects of feeding Cistus ladanifer (Cistus) and a blend of soybean and linseed oil (1 : 2 vol/vol) on fatty acid (FA) composition of lamb meat lipids and messenger RNA (mRNA) expression of desaturase enzymes was assessed. In total, 54 male lambs were randomly assigned to 18 pens and to nine diets, resulting from the combination of three inclusion levels of Cistus (50 v. 100 v. 200 g/kg of dry matter (DM)) and three inclusion levels of oil (0 v. 40 v. 80 g/kg of DM). The forage-to-concentrate ratio of the diets was 1 : 1. Longissimus muscle lipids were extracted, fractionated into neutral (NL) and polar lipid (PL) and FA methyl esters obtained and analyzed by GLC. The expression of genes encoding Δ5, Δ6 and Δ9 desaturases (fatty acid desaturase 1 (FADS1), fatty acid desaturase 2 (FADS2) and stearoyl CoA desaturase (SCD)) was determined. Intramuscular fat, NL and PL contents were not affected by oil or Cistus. Oil supplementation reduced (P<0.05) 16:0, c9-16:1, 17:0, c9-17:1 and c9-18:1 FA and increased (P<0.05) 18:2n-6, 18:3n-3 and the majority of biohydrogenation intermediates in NL. Cistus alone had few effects on FA of NL but interacted with oil (P<0.05) by increasing t10-18:1,t10,t12-18:2,t10,c12-18:2 and t7,c9-18:2. The t10-/t11-18:1 ratio increased with both Cistus and oil levels. The c9, t11-18:2 did not increase (P<0.05) with both oil and Cistus dietary inclusion. Oil reduced c9-16:1, 17:0, c9-17:1,c9-18:1, 20:4n-6, 22:4n-6 and 20:3n-9 proportions in PL, and increased 18:2n-6, 18:3n-3, 20:3n-3 and of most of the biohydrogenation intermediates. The Cistus had only minor effects on FA composition of PL. Cistus resulted in a reduction (P<0.05) of 20:5n-3 and 22:6n-3 in the meat PL. The expression level of SCD mRNA increased (P=0.015) with Cistus level, although a linear relationship with condensed tannins intake (P=0.11) could not be established. FADS1 mRNA expressed levels increased linearly (P=0.019) with condensed tannins intake. In summary, the inclusion of Cistus and oil in 1 : 1 forage-to-concentrate ratio diets resulted in a large increase in t10-18:1 and no increase in c9,t11-18:2 or n-3 long chain poor in polyunsaturated fatty acids in lamb meat. [ABSTRACT FROM PUBLISHER]

This study assessed the effect of Spirulina (Arthrospira platensis), individually and in combination with exogenous enzymes, on growth performance, carcass traits, and meat quality of broiler chickens. One hundred and twenty Ross 308 male chickens were allocated into 40 battery brooders, with 3 birds per cage, and fed ad libitum a corn-based diet during the first 21 D of the trial. The experimental period lasted from day 21 to 35, during which birds were fed 4 different diets: a corn-soybean basal diet, taken as the control group, a basal diet containing 15% Spirulina (MA), a basal diet containing 15% Spirulina plus 0.005% Rovabio Excel AP (MAR), and a basal diet containing 15% Spirulina plus 0.01% lysozyme (MAL). Body weight gain (P, 0.001) and feed conversion rate (P, 0.001) were improved in control chickens, when compared with those fed with Spirulina. In addition, Spirulina increased the length of duodenum plus jejunum in relation to the other treatment (P, 0.01). Chickens on the MAL diet showed a considerable increase in digesta viscosity (P, 0.05) compared with the control group. Breast and thigh meats from chickens fed with Spirulina, with or without the addition of exogenous enzymes, had higher values of yellowness (b*) (P, 0.001), total carotenoids (P, 0.001), and saturated fatty acids (P, 0.001), whereas n-3 polyunsaturated fatty acid (P, 0.01) and a-tocopherol (P, 0.001) decreased, when compared with the control. In conclusion, the incorporation of 15% Spirulina in broiler diets, individually or combined with exogenous enzymes, reduced birds’ performance through a higher digesta viscosity, which is likely associated with the gelation of microalga indigestible proteins. In addition, cell wall of Spirulina was successfully broken by the addition of lysozyme, but not by Rovabio Excel AP. Therefore, we anticipate that the combination of lysozyme with an exogenous specific peptidase could improve the digestibility of proteins from this microalga and avoid their detrimental gelation. [ABSTRACT FROM AUTHOR]

Laminaria digitata is a brown seaweed rich in prebiotic polysaccharides, mainly laminarin, but its alginate-rich cell wall could compromise nutrient access. Carbohydrase supplementation, such as individual alginate lyase and carbohydrases mixture (Rovabio® Excel AP), could enhance nutrient digestibility and prebiotic potential. This study aimed to evaluate the effect of these enzymes on nutrient digestibility and gut health of weaned piglets fed with 10% L. digitata. Diets did not affect growth performance (P > 0.05). The majority of the feed fractions had similar digestibility across all diets, but the supplementation of alginate lyase increased hemicellulose digestibility by 3.3% compared to the control group (P = 0.047). Additionally, we observed that algal zinc was more readily available compared to the control group, even without enzymatic supplementation (P < 0.001). However, the increased digestibility of some minerals, such as potassium, raises concerns about potential mineral imbalance. Seaweed groups had a higher abundance of beneficial bacteria in colon contents, such as Prevotella, Oscillospira and Catenisphaera. Furthermore, the addition of alginate lyase led to a lower pH in the colon (P < 0.001) and caecum (P < 0.001) of piglets, which is possibly a result of released fermentable laminarin, and is consistent with the higher proportion of butyric acid found in these intestinal compartments. L. digitata is a putative supplement to enhance piglet gut health due to its prebiotic polysaccharides. Alginate lyase supplementation further improves nutrient digestibility and prebiotic potential. These results suggest the potential use of L. digitata and these enzymatic supplements in commercial piglet-feeding practices., (Copyright © 2024 The Author(s). Published by Elsevier B.V. All rights reserved.)

This study focused on the application of three strains of Lacticaseibacillus paracasei to assimilate cholesterol in cream and butter. The strains were enclosed in calcium-alginate beads and incubated in cream at 30 °C for 15 h. Immobilization of lactobacilli cultures in calcium-alginate beads resulted in a 23% reduction in cholesterol (p < 0.05) in cream, whereas a negligible reduction was observed in cream fermented with free cells. Butter with a 44% reduction in cholesterol was produced from fermented cream by L. paracasei L2A21K5 entrapped in alginate beads. No significant (p > 0.05) changes in the fatty acid profile were observed in the low-cholesterol butter, except for a slight but significant increase in n-3 fatty acids (p < 0.05). In addition, the indices of atherogenicity and thrombogenicity were significantly reduced in the low-cholesterol butter (p < 0.05). Panelists rated the low-cholesterol butter as good in appearance, consistency, and flavor., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Herein, we investigated the effect of Chlorella vulgaris as ingredient (10% of incorporation) in broiler diets, supplemented or not with 2 formulations of Carbohydrate-Active enZymes (CAZymes; Rovabio Excel AP and a mixture of recombinant CAZymes, composed by an exo-β-glucosaminidase, an alginate lyase, a peptidoglycan N-acetylmuramic acid deacetylase and a lysozyme), on growth performance, meat quality, fatty acid composition, oxidative stability, and sensory traits. One hundred twenty 1-day-old Ross 308 male birds were randomly assigned to one of the 4 experimental diets (n = 30): corn-soybean meal-basal diet (control), basal diet with 10% C. vulgaris (CV), CV supplemented with 0.005% of a commercial CAZyme cocktail (Rovabio Excel AP), (CV + R), and CV supplemented with 0.01% of a 4-CAZyme mixture previously selected (CV + M) during the experimental period lasted from day 21 to day 35. Body weight gain and feed conversion rate of broilers were not affected by C. vulgaris but digesta viscosity increased more than 2-fold (P < 0.001) relative to the control. In addition, neither cooking loss, shear force, juiciness, flavor nor off-flavor was impaired by dietary treatments (P > 0.05). By contrast, the dietary C. vulgaris increased tenderness, yellowness (b∗) and total carotenoids in breast and thigh meats. However, no additional protective effect against lipid oxidation was observed in meat with the inclusion of microalga. Chlorella vulgaris, independently of CAZymes, had a minor impact on meat fatty acid composition but improved the proportion of some beneficial fatty acids. In summary, our data indicate a slight improvement of broiler meat quality and lipid nutritional value, without impairment of broilers' growth performance, thus supporting the usefulness of this microalga in poultry diets, up to this high level of incorporation. By contrast, the selected CAZyme mixtures used do not significantly improve the release of microalga nutrients in poultry diets, through the disruption of microalga cell wall, which warrants further research., (Copyright © 2020. Published by Elsevier Inc.)

Pork, one of the most consumed meats worldwide, has been facing major challenges regarding its low sensory quality and unhealthy image of fat. This chapter addresses current feeding strategies to ameliorate pork sensory attributes and nutritional quality by increasing intramuscular fat deposition and improving fatty acid composition, respectively. Dietary protein reduction, alone or combined with some components, contributes to satisfy consumer requirements and enhances the competitiveness of the meat industry with higher pork quality and lower production costs. In addition, feeding sources of n-3 polyunsaturated fatty acids to pigs, mainly from marine origin (rich in eicosapentaenoic and docosahexaenoic acids), increases their content in pork, thus improving the health value of its fatty acid profile. In the near future, the inclusion of microalgae and seaweeds in feed represents a promising approach for the maintenance and development of the livestock sector, as an environmental friendly alternative to balance food and feed industries., (© 2019 Elsevier Inc. All rights reserved.)

An essential role of prion protein testis specific (PRNT) and prion protein 2 dublet (PRND) genes in the male reproductive function has been highlighted, although a deeper knowledge for the mechanisms involved is still lacking. Our goal was to determine the importance of the PRNT haplotypic variants and mRNA expression levels in ovine spermatozoa freezability and ability for fertilization and embryo developmental processes. Their association with the PRND gene polymorphisms was also analyzed. DNA from rams belonging to three Portuguese sheep breeds (n = 28) was screened by single-strand conformation polymorphism (SSCP) analysis to identify the PRNT and PRND polymorphisms. Semen collected from these rams was cryopreserved and fertility traits evaluated. The SSCP analyses revealed polymorphisms in the codons 6, 38, 43 and 48 of the PRNT coding region - respectively c.17C > T (p.Ser6Phe, which disrupts a consensus arginine-X-X serine/threonine motif); c.112G > C (p.Gly38 > Arg); and synonymous c.129T > C and c.144A > G. The polymorphisms in codons 6, 38 and 48 occur simultaneously while the one in codon 43 occurs independently. Six haplotypes were identified in the PRNT coding region, resulting in three different amino acid polymorphic variants (6S-38G-43C-48V, S6F-G38R-43C-48V and 6F-38R-43C-48V). The PRNT gene mRNA transcript level in spermatozoa was related to the identified haplotypic variants, either considering the codons 6-38-48 (P ≤ 0.0001) or the codon 43 alone (P ≤ 0.0001) or altogether (P ≤ 0.0001). An interaction between PRNT haplotypes and PRND genotypes on PRNT transcript level was also identified (P = 0.0003). Rams carrying the 17C-112G-144A PRNT haplotype had sperm with the highest post-thawed individual motility (P ≤ 0.03). Combined PRNT and PRND polymorphic variation influenced the post-thawed individual motility (P = 0.01). The male PRNT haplotypic, either considering the codons 6-38-48 and 43 altogether or the codon 43 alone, interfered (P ≤ 0.04) in embryo production rates. In conclusion, our data confirm that the PRNT gene is highly polymorphic in sheep and that the PRNT and PRND genotypes are associated. The identified polymorphisms of PRNT coding region seems to interfere on the ram spermatozoa mRNA transcript level and on male fertility, specifically in sperm freezability and ability for embryo development., (Copyright © 2018. Published by Elsevier Inc.)