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Simple Summary: Oleanolic acid is an organic natural compound, abundant in olive leaves, with various beneficial health effects in humans and animals. However, its in vivo efficacy is questioned given its low solubility, which hinders its bioavailability, that is, the capacity of a molecule to reach circulation. We investigated the digestibility and plasma concentration of oleanolic acid as an estimate of bioavailability in growing pigs. Because it is important to know the effects of oleanolic acid in the animal, growth, organ weights, digestibility of nutrients and plasma biochemical profile have been reported as well. Although there is a concern in the scientific community regarding the low bioavailability of oleanolic acid, in vivo data are lacking. We have demonstrated that, while digestibility of oleanolic acid was unexpectedly elevated, the appearance of the molecule in systemic blood was weak, probably indicating hepatic metabolism. No negative effects of oleanolic acid on growth or internal organs were observed. Oleanolic acid (OLA) has beneficial health effects in animals, but in vivo efficacy in monogastric animals is questioned due to its low bioavailability. To gain further insight on the nutritional effects of OLA it was administered as part of a diet. We investigated digestibility and plasma OLA in pigs and the associated influence on growth, organs, digestibility of nutrients and plasma biochemical profile. Twenty-four crossbred barrows (23.7 ± 1.0 kg BW) were assigned one of three treatments: Control (basal diet without OLA), OLA-1 (basal diet with 260 mg/free OLA) and OLA-2 (basal diet with 260 mg/kg cyclodextrin-OLA). Diets included chromium oxide to estimate digestibility. Blood samples were collected on day 14 for OLA analysis and feces on days 22–24 for determining digestibility. Pigs were slaughtered on day 31 (39.9 ± 2.43 kg BW) and their blood collected for analysis. Growth and organ weights were not affected (p > 0.05). OLA-1 decreased apparent total tract digestibility (ATTD) of energy (p < 0.05). OLA-2 increased ATTD of dry and organic matter compared with Control pigs (p < 0.05). OLA-1 increased plasma calcium and alkaline phosphatase (p < 0.05). Ileal digestibility of OLA was not affected (0.88), although OLA ATTD increased in OLA-1 compared to Control pigs (0.75 vs. 0.82; p < 0.05). OLA-1 and OLA-2 increased plasma OLA compared to Control pigs (p < 0.05 and p = 0.083). In conclusion, although the OLA was digested and absorbed, plasma concentration was low (4.29 µg/L), and pig growth, organs and plasma parameters were not affected. [ABSTRACT FROM AUTHOR]

Simple Summary: As pigs are sensitive to heat, high temperature produces large economic losses in pig production. The Iberian pig (Sus mediterraneus) is a rustic breed that thrives in the Mediterranean forest in the southwest of the Iberian Peninsula, with hot summers, with a peak in July (32–36 °C) being more frequent due to the appearance of heatwaves in the Mediterranean area. It is well known that betaine and zinc are growth promoters in pigs under thermoneutral conditions. Betaine acts as an osmolyte, decreasing basal heat production, and zinc is very important as an enzymatic cofactor and structural element for proteins, and improves intestinal functionality. Whether betaine and zinc may mitigate heat stress in pigs remains unclear. Our aim was to study the effect of heat, and the dietary supplementation of betaine or zinc on the heat production of Iberian pigs. At 30 °C, betaine or zinc supplementation had no effect on heat production; in addition, these parameters were not affected by temperature, indicating that Iberian pigs are well adapted to hot environments. However, the ratio of CO2 production/O2 consumption indicated that supplementation with betaine may have a positive effect on lipogenesis and, thereafter, overall growth. The effect of heat, and dietary betaine or zinc on the heat production (HP) of Iberian pigs was studied. Thirty barrows (44 kg) were individually housed for 28 days and assigned to one of five treatments: (1) thermoneutrality (20 °C) and fed a control diet (TN-CON) ad libitum; (2) hot (30 °C) and fed a control diet (HT-CON) ad libitum; (3) thermoneutrality and pair fed a control diet (TN-CON-PF) to HT-CON; (4) hot and fed a betaine-supplemented (0.5%) diet (HT-BET) ad libitum; and (5) hot and fed a zinc-supplemented (0.012%) diet (HT-ZN) ad libitum. On the 18th day, pigs were moved to a respirometry chamber (two chambers) under their respective treatment. The metabolizable energy (ME) intake, HP and respiratory quotient (RQ) were measured over 24 h. No differences (p > 0.05) were found in HP and RE between treatments. For RQ, TN-CON was greater (p < 0.01) than HT treatments, except for HT-BET. All RQs indicated an overall lipogenesis where betaine supplementation showed an intermediate value, indicating that it may have a positive effect on lipogenesis and overall growth. At 30 °C, betaine or zinc had no effect on HP and RE; ME intake was not reduced, indicating a genetic adaptation of Iberian pigs to heat. [ABSTRACT FROM AUTHOR]

Simple Summary: Pig immunocastration—vaccination against the gonadotropin-releasing hormone—prevents sexual development and boar taint, an unpleasant odor perceived in pork products. It is a feasible alternative to surgical castration that considerably increases pig well-being. Apart from this benefit, immunocastrated pigs perform better than surgically castrated pigs, which is of interest for pig production in general, and for native pig breeds in particular, as they show slow growth and lean tissue deposition compared to cosmopolitan pig breeds. These performance benefits were demonstrated in immunocastrated Iberian male pigs, a local pig breed from the Iberian Peninsula. The purpose of the study was to investigate the metabolic profile of immunocastrated male and female Iberian pigs compared to surgically castrated male pigs, which is the standard pig type for Iberian pig production. The surgically castrated males showed metabolic features of pigs prone to deposit more lipids, with less lean tissue and they were less sensitive to circulating insulin, whereas immunocastrated males presented increased plasmatic concentrations of some key amino acids and hormones (IGF-1) related to enhanced protein deposition. The immunocastrated female group showed intermediate traits. The results support the higher performance previously observed in immunocastrated male Iberian pigs compared to surgically castrated males and immunocastrated females. The purpose of the current study was to further characterize the performance and nitrogen retention differences previously observed between immunocastrated (IC) and surgically castrated (SC) pure Iberian pigs. Fifty-four pigs were used (three sexes: IC males, IC females and SC males), fed three isoenergetic diets (160, 140 and 120 g CP/kg DM; six pigs/treatment combination) from 40 kg BW until slaughter (105 kg BW). Plasmatic post-absorptive metabolites and hormones, and backfat tissue composition were determined. The IC males showed a trend towards higher plasmatic creatinine (p = 0.06) and IGF-1 concentrations than SC males and IC females (p < 0.001). SC males showed a higher predisposition to carcass fatness and insulin resistance compared to IC males. Plasmatic isoleucine concentration was higher in IC and SC males compared to IC females (p < 0.01), and valine was greater in IC males compared to the rest of the pigs (p < 0.001). Total branched-chain amino acids (AA) were greater in IC males than in IC females (p < 0.01). Total plasmatic essential AA concentrations tended to be greater in IC males (p = 0.09). The present results support the increased performance and nitrogen retention capacity previously observed in IC male Iberian pigs compared to SC males and IC females, which can be attributed to increased anabolic capacity related with lean growth in Iberian IC males. [ABSTRACT FROM AUTHOR]

Simple Summary: Iberian pig (Sus mediterraneus) is a rustic breed that thrives in the Mediterranean forest in the Southwest of the Iberian Peninsula, traditionally raised in open range, grazing acorn and grass. The information on nutrient requirements of Iberian pigs compared with modern breeds is scarce and derived from modern breeds, even though there are evidences that they have distinct metabolic and nutritional features, showing a much lower growth rate and protein deposition. This study attempts to shed light on this issue. By using net portal appearance, the intestinal absorption of nutrients is considered, and therefore the nutrient availability for pig growth is estimated. The present study focused on the net portal appearance of amino acids in Iberian pigs compared to a modern breed known as Landrace. Iberian pigs showed a lower net portal appearance of amino acids than Landrace pigs, regardless of the content of protein in the diet. Differences in net portal appearance of amino acids may partially explain the lower growth rate of Iberian pigs compared to modern breeds, maybe as result of a greater use of amino acids by the gastrointestinal tract. Strategies supplementing key gut amino acids in support of gut function may improve pig performance during the productive period. Iberian pigs have low rates of muscle protein deposition compared with modern breeds. Differences in net portal appearance (NPA) of amino acids (AA) might partially explain that. NPA of AA was measured in six Iberian and six Landrace gilts (28 kg) fitted with catheters in portal and mesenteric (para-aminohippuric acid infusion) veins, and carotid artery. Blood samples from porta and artery were simultaneously taken at 0, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 5, and 6-h after feeding two isoenergetic diets (14–14.5 MJ metabolizable energy/kg dry matter) with different crude protein (145 (LCP) and 187 (HCP) g/kg dry matter) content. NPA of essential AA (EAA) and non-essential AA (NEAA) was lower (p < 0.05) in Iberian than Landrace pigs, and in LCP than HCP diet. Fractional absorption (NPA/AA intake) of EAA, NEAA, and total AA was, respectively, 36, 49, and 44% lower in LCP than HCP diet in Iberian pigs; and 8, 2, and 4% greater in Landrace pigs. Fractional absorption of EAA, NEAA, and total AA was 42, 68, and 60% lower in Iberian than Landrace pigs fed LPC diet; and 1, 36, and 26% when fed the HCP diet. NPA of AA may partially explain the low growth rate of Iberian pigs. [ABSTRACT FROM AUTHOR]

Simple Summary: Heat stress has negative consequences in animal husbandry and pigs are highly susceptible because of their scattered sweat glands and elevated metabolic rate. Above 25 °C, pigs trigger mechanisms such as diverting blood from their internal organs to skin or decreasing the feed intake, which can affect the intestinal microbiota and capacity of fermentation. Betaine and zinc have been used as nutritional mitigation strategies to alleviate the effects of heat stress in pigs, but their effects on hindgut fermentation are unknown. By using an in vitro fermentation system and employing as the inoculum the rectal content from heat-stressed Iberian pigs supplemented or not with betaine or zinc, we showed that both supplements modified the pattern of hindgut fermentation in heat stressed pigs, having beneficial effects on acetate and butyrate production. The abundance of some bacterial groups was also modified, indicating an effect on the microbial structure. Because of the intricate interactions between the host and gut microbiota, additional studies are necessary to confirm these results under in vivo conditions. We investigated the effects of betaine and zinc on the in vitro fermentation of pigs under heat stress (HS). Twenty-four Iberian pigs (43.4 ± 1.2 kg) under HS (30 °C) were assigned to treatments for 4 weeks: control (unsupplemented), betaine (5 g/kg), and zinc (0.120 g/kg) supplemented diet. Rectal content was used as the inoculum in 24-hincubations with pure substrates (starch, pectin, inulin, cellulose). Total gas, short-chain fatty acid (SCFA), and methane production and ammonia concentration were measured. The abundance of total bacteria and several bacterial groups was assessed. Betaine increased the acetate production with pectin and inulin, butyrate production with starch and inulin, and ammonia concentration, and decreased propionate production with pectin and inulin. The abundance of Bifidobacterium and two groups of Clostridium decreased with betaine supplementation. Zinc decreased the production of SCFA and gas with starch and inulin, associated with diminished bacterial activity. Propionate production decreased with starch, pectin, and inulin while butyrate production increased with inulin, and isoacid production increased with cellulose and inulin in pigs supplemented with zinc. The ammonia concentration increased for all substrates. The Clostridium cluster XIV abundance decreased in pigs fed zinc supplemented diets. The results reported were dependent on the substrate fermented, but the augmented butyrate production with both betaine and zinc could be of benefit for the host. [ABSTRACT FROM AUTHOR]

Heat stress is associated with impaired meat quality and disruption of redox balance. This study investigated the effect of chronic exposure to high temperature on meat quality and antioxidant markers of muscles (longissimus lumborum and gluteus medius) of growing Iberian pigs. Twenty-four pure Iberian pigs were allocated during 28 days to one of three treatments (n = 8/treatment): thermoneutral conditions (20 °C) and ad libitum feeding (TN), heat stress conditions (30 °C) and ad libitum feeding (HS) and thermoneutral and pair-fed with HS (TN-pf). Muscles of the HS group had greater intramuscular fat content than the TN-pf group and higher Zn levels than TN and TN-pf, whereas differences on fatty acid composition were negligible. Heat exposure did not affect pH, color coordinates of redness (a*) and yellowness (b*) and MDA values but had a positive influence on lightness and drip losses. Moreover, chronic heat stress stimulated the activity of antioxidant defenses SOD, CAT and GPx. The statistical factor analysis adequately classified the muscles studied, but was unable to differentiate samples according with treatments. Findings of the present study support an adaptive response of the Iberian pig to high temperatures and show the high Iberian meat quality even under adverse climate situations. [ABSTRACT FROM AUTHOR]

Simple Summary: Heat stress is a major concern in pig production in summer, as pigs have a limited number of functional sweat glands to transfer body heat. Above 25 °C pigs are out of their comfort zone and mechanisms such as decreasing feed intake or diverting blood from the internal organs to the skin are triggered. Intestinal microbiota is also affected by high ambient temperature but the consequences on fermentation capacity are poorly known. Short-chain fatty acids are the end-products of bacterial metabolism of carbohydrates and protein mainly in the hindgut and, in addition to being a source of energy, they have beneficial effects on immune status and health. An understanding of the effects of heat stress on intestinal fermentation could help to develop strategies mitigating intestinal disorders. We used an in vitro method to assess gas and short-chain fatty acid production, utilizing as inoculum feces from Iberian pigs fed a commercial diet for 28 days under neutral (20 °C) or heat stress (30 °C) conditions. Four substrates with dissimilar fermentation characteristics were incubated in vitro with fecal inoculum for 24 h. Chronic heat stress increased in vitro production of short-chain fatty acids, suggesting a modification of intestinal microbiota activity. Heat stress reduces the feed intake and growth of pigs. We hypothesized that heat stress affects the intestinal fermentation capacity of pigs. Sixteen Iberian pigs (44 ± 1.0 kg) were randomly assigned to one of two treatments (eight pigs/treatment) for 4 weeks—heat stress (HS; 30 °C) ad libitum or thermoneutral (TN; 20 °C) pair feeding. Frozen rectum contents were used as inocula for 24 h in vitro incubations in which a mixture of starches, citrus pectin, inulin from chicory, and cellulose were the substrates. Cellulose was poorly degraded, whereas pectin and the mixture of starches were the most fermentable substrates according to total short-chain fatty acid (SCFA) production. The mixture of starches and inulin produced the greatest amount of gas. For all substrates, heat stress enhanced gas production (8%, p = 0.001), total SCFA production (16%, p = 0.001), and the production of acetate and propionate (12% and 42%, respectively; p = 0.001). The increased isoacid production (33%, p = 0.001) and ammonia concentration (12%, p = 0.001) may indicate protein fermentation under heat stress. In conclusion, the in vitro intestinal fermentation capacity of pigs under heat stress was increased compared to thermoneutral conditions, which may indicate an adaptive response to heat stress. [ABSTRACT FROM AUTHOR]