Diet Feeding Research Articles

Effect of feeds and hygienic practices on milk production and its nutritional and microbiological quality

Abstract The review emphasizes that factors such as feed type, diet composition, and hygiene standards during milking significantly impact milk yield, composition, and microbial population. A comprehensive methodology was employed to gather relevant literature from diverse sources, including textbooks, academic journals, and databases. The review focused on research articles investigating the impact of feed type and nutrients on dairy cattle milk yield, and quality. The search terms used to organize this article were breed, feed, hygienic practices, sources of microorganisms, and milk production, and by synthesizing findings from these studies; key factors influencing milk production and quality were identified. The review highlights the significance of breed selection, feeding practices, and hygienic measures in dairy farming. Optimizing these factors can enhance milk production, nutritional quality, and microbial safety, ensuring the delivery of high-quality milk to consumers. Overall, the review provides valuable insights into the relationship between animal breed, nutrition, and hygiene practices in dairy cattle production.

Different oil sources impacting brain lipid and transcriptome profiles of pigs

Lipids are fundamental to the structure and function of the brain, and their fatty acids (FA) composition is rich in polyunsaturated fatty acids (PUFA), which have protective effects and modulate gene transcription. For nutrigenomics studies, pigs (Sus scrofa) have been widely used as a biomedical model. Thus, the aimed to investigate whether different dietary oil sources modify the pig brain's lipid and transcriptomic profile. A 98-day study was performed using fifty-four male pigs. Treatments consisted of corn-soybean meal diets containing 3 % of soybean oil (SOY), canola oil (CO), or fish oil (FO). Total mRNA was extracted for sequencing. As a result, feeding diets with different oil sources affected the percentage of some FA. Palmitic acid showed a greater concentration in diets containing SOY with 27.037 %. Oleic acid and eicosenoic acid, showed a greater concentration in diets containing SOY, with 30.968 % and 2.096 %, respectively; and, total PUFA showed a better concentration in diets containing SOY and FO, with 11.685 % and 12.150 %, respectively. After quality control, considering the total reads obtained for the three groups, 94.87% were mapped against the reference genome SScrofa11.1. A comparison of gene expression between the groups of pigs was carried out by using the DESeq2 statistical package (R/Bioconductor). From SOY vs CO comparison, five differentially expressed genes (DEG, FDR < 0.05) were identified, from SOY vs FO forty-four DEG were verified, and from CO vs FO thirty-nine DEG were found. The functional enrichment analysis resulted in pathway maps (P < 0.05) related to apoptosis and cell proliferation, obesity and type 2 diabetes, neurophysiological process, and inflammation. The networks were associated with signal transduction, calcium transport, and oxidative stress. Overall, the results showed that diets with different oil sources could affect some brain tissue parameters and may help guide future research on the availability of dietary FA in the brain.

FicD regulates adaptation to the unfolded protein response in the murine liver

The unfolded protein response (UPR) is a cellular stress response that is activated when misfolded proteins accumulate in the endoplasmic reticulum (ER). Regulation of the UPR response must be adapted to the needs of the cell as prolonged UPR responses can result in disrupted cellular function and tissue damage. Previously, we discovered that the enzyme FicD (also known as Fic or HYPE) through its AMPylation and deAMPylation activity can modulate the UPR response via post-translational modification of BiP. FicD AMPylates BiP during homeostasis and deAMPylates BiP during stress. We hypothesized that FicD regulation of the UPR will play a role in mitigating the deleterious effects of UPR activation in tissues with frequent physiological stress. Here, we explore the role of FicD in the murine liver. As seen in our pancreatic studies, livers lacking FicD exhibit enhanced UPR signaling in response to short term physiologic fasting and feeding stress. However, in contrast to studies on the pancreas, livers, as a more regenerative tissue, remained remarkably resilient in the absence of FicD. The livers of FicD−/− did not show marked changes in UPR signaling or damage after either chronic high fat diet (HFD) feeding or acute pathological UPR induction. Intriguingly, FicD−/− mice showed changes in UPR induction and weight loss patterns following repeated pathological UPR induction. These findings indicate that FicD regulates UPR responses during mild physiological stress and in adaptation to repeated stresses, but there are tissue specific differences in the requirement for FicD regulation.

The impact of functional feed on Atlantic salmon (Salmo salar) systemic immune response to high and low levels of sea lice infection (Lepeophtheirus salmonis) and co-infection with infectious salmon anemia virus

Due to the nature of open-pen farming, salmon are exposed to numerous pathogens shared by other farms and their wild counterparts. Industry must manage these outbreaks through vaccination, oral or bath treatments, and more recently through functional feed administration. Globally, the most important pathogens of salmon are sea lice (Lepeophtheirus salmonis, and Caligus rogercresseyi) not only due to their direct impacts on the host, but indirectly by enhancing host susceptibility to co-infection. This study aims to characterize molecular responses during a co-infection of L. salmonis and a salmon orthomyxovirus (infectious salmon anemia virus; ISAv) under administration of four functional feed diets: a control feed with a low 0.3 % EPA/DHA + high-ω6 (Ctrl), an EPA/DHA enriched pro-inflammatory diet 1 % EPA/DHA + high-ω6; FA + I), an EPA/DHA enriched anti-inflammatory diet (1 % EPA/DHA+high-ω3; FA-I), and a low EPA/DHA feed (0.3 %) with an immunostimulant added (0.3 % EPA/DHA + high-ω6 + immunostimulant (IS); Ctrl + IS). Atlantic salmon (40 fish per tank; 8 tanks per feed) were acclimated to one of the four experimental diets. Sea lice copepodids were introduced to all experimental tanks and 10 fish sampled from each tank at each time point (prior to infection [−3], and 11, 33, 47 days post infection). A high virulence ISAv isolate (ISAV-HPR4) was intraperitoneally injected into donor fish 6 days prior to their transfer into the experimental tanks for cohabitation (ca. 10–15 % of tank density; 4 tanks per feed group) to achieve peak shedding rates at time of stocking. Fatty acid enriched (FA + I and FA-I) diets had a significant impact on sea lice abundance on fish infected with lice only. Gene expression profiles measured by reverse transcriptase-qPCR showed significant upregulation in several antiviral genes (irf7b and mxb) associated with the interferon system in all but the fish fed the immunostimulating diet. An increase in transcript levels (irf7b, isg15a, mmp-9, mxb) accounted for high lice and high viral loads in diets FA + I and Ctrl + IS. As feeds successful at reducing lice were the least successful in survival of co-infected fish, there appears to be a trade-off for better anti-parasitic responses, which is enhanced through dietary supplementation. This will require further research to ensure careful selection of feed combinations and expected co-infection challenges.

252 Evaluation of phase feeding and complete diet blending at different standardized ileal digestible lysine levels on finishing pig growth performance, carcass characteristics and diet costs

Abstract A total of 2,160 mixed-gender pigs [PIC 337 × 1050; initial body weight (BW) = 24.9 ± 0.97 kg) were used in the 120-d study to compare feeding strategies (phase feeding vs complete diet blending) at different SID Lys levels (90 vs 100% of suggested requirement estimates) on finishing pig growth performance, carcass characteristics, and economics. Pens of 27 pigs were assigned to 1 of 4 treatments in a completely randomized block design with barn and initial BW as blocking factors resulting in 20 pens/treatment. The treatments included two feeding programs: a 5-phase feeding strategy at either 90% (Phase-90) or 100% of SID Lys requirement estimates (Phase-100) or blending of complete diets with pre-defined mixing proportions of a low and high SID Lys diet to meet 90 (Blend-90) or 100% (Blend-100) of the SID Lys curve requirement estimates for 23 to 127 kg pigs. Lysine levels were based on PIC 2021 requirement estimates. The 90% SID Lys diets were formulated to contain 4.38, 3.73, 3.06, 2.66 and 2.44 g SID Lys per Mcal NE for phases 1 to 5, respectively. The 100% SID Lys diets were formulated to contain 4.86, 4.15, 3.40, 2.96 and 2.71 g SID Lys per Mcal NE for phases 1 to 5, respectively. Pigs in phase-feeding strategies were fed on a feed budget with 21, 65, 67, 63 and 62 kg per pig for phases 1 to 5, respectively. Final BW and overall average daily gain (ADG; d 0 to 120) were not affected by the feeding strategy nor by diet SID Lys levels. In contrast, overall average daily feed intake (ADFI0 of pigs fed by diet blending was less than those fed by phase feeding (P = 0.002) resulting in increased gain to feed ratio (G:F; P &amp;lt; 0.001) for pigs fed by diet blending (table). The SID Lys levels did not influence overall ADFI or G:F. Hot carcass weight, carcass yield, percentage lean, fat depth and loin depth were not affected by the feeding program. Despite the decreased overall ADFI and increased G:F of pigs fed by diet blending, feeding strategy resulted in no significant differences in economic criteria except for reduced feed cost per kg gain at high price scenario (P = 0.049) for diet blending. With low diet cost, the 90% SID Lys level resulted in decreased feed cost per pig and feed cost per kg gain than 100% SID Lys (P &amp;lt; 0.001), but differences were not detected in income over feed cost (IOFC). In conclusion, diet blending at either 90 or 100% of the SID Lys requirement estimate reduced ADFI and increased G:F without impacting average daily gain (ADG) or carcass characteristics. At ingredient prices used in this study, feeding strategies at either 90 or 100% SID Lys did not significantly affect IOFC, but feeding 90% of SID Lys recommendation reduced feed cost.

PSI-8 Impact of feeding level on boars from selection to entering the boar stud on trainability and growth measurements

Abstract The objective of this study was to determine if restricting feed in boars at selection impacts growth of boars or training for semen collection. Duroc boars (n = 25) randomly allotted at 6 mo of age to receive one of two levels of restricted feeding (1.8 kg/d, n = 12 or 2.72 kg/d, n = 13) of a corn-soybean meal-based diet formulated to meet NRC (2012) requirements. Diets were fed for 9 wk before training for semen collection where body weight (BW), body condition score (BCS), flank-flank tape measurements, Knauer sow caliper, loin muscle depth, backfat depth, and scrotal width and length were collected every 3 wk. Training for semen collection was conducted 5 d/wk for 2 wk. Boars were given 10 min in the collection pen to successfully mount the dummy and start collection each training session. Training was scored on a scale of 1-5, 1 = no interest and 5 = successful collection. After three successful collections in a row, boars were considered fully trained. All boars had their first production collection on wk 12. Data were analyzed using PROC MIXED and PROC FREQ chi-square in SAS 9.4 with boar serving as experimental unit. Weeks were analyzed individually and overall changes were evaluated. Significance was determined at P &amp;lt; 0.05 and a trend was observed at 0.05 &amp;lt; P ≤ 0.10. Boars fed 2.72 kg/d had increased BW on wk 9 (P &amp;lt; 0.05) and wk 12 (163.6 kg vs 149.8 kg, SE = 2.17; P &amp;lt; 0.001), increased BW gain wk 1-9 (P &amp;lt; 0.01), wk 9-12 (P &amp;lt; 0.001), and overall (49.8 kg vs 34.4 kg, SE = 1.60; P &amp;lt; 0.0001). The 2.72 kg/d boars also had increased backfat depth on wk 9 (P &amp;lt; 0.01) and wk 12 (8.4 mm vs 7.5 mm, SE = 0.17; P &amp;lt; 0.001), larger caliper scores on wk 12 (P &amp;lt; 0.01), greater flank-flank distance on wk 9 (P &amp;lt; 0.01), and increased BCS on wk 12 (3.2 vs 2.7, SE = 0.14; P &amp;lt; 0.01). No differences were observed for loin muscle depth, or scrotal width and length. Feeding level did not affect trainability with approximately 92% of boars being trained at the end of the two-week period in both feeding levels. Boars fed 2.72 kg/d had increased semen volume (128 mL vs 81 mL, SE = 12.1; P &amp;lt; 0.01) on their first production collection on wk 12 with no effects on other semen quality parameters. Overall, feeding boars 1.8 kg/d for 12 weeks following selection resulted in lower body weight and composition measures indicating limit feeding boars at selection could be used to slow growth rates, potentially decreasing structural issues, and increasing longevity of growing boars in the boar stud, with no effects on training for semen collection. Future research is needed to investigate the long-term impacts of the degree of limit feeding growing boars following selection on lifetime semen quality and quantity. Keywords boar, management, nutrition

PSI-5 Evaluation of EhV (surrogate for African swine fever virus) inactivation in corn- and soybean-based feed ingredients and diets at various times and temperatures during storage

Abstract African swine fever virus (ASFV) is a member of the nucleocytoplasmic large DNA viruses (NCLDVs) and remains stable in a variety of environments, including animal feed ingredients as shown in previous laboratory experiments and simulations. Emiliania huxleyi virus (EhV) is another member of NCLDV, which has a restricted host range limited to a species of marine algae called Emiliania huxleyi. This algal NCLDV has many similar morphological and physical characteristics to ASFV which makes it a safe and reliable surrogate for studying ASFV survival and inactivation in feed ingredient matrices in-situ under various time and temperature storage conditions. The objective of the present study was to investigate the inactivation of ASFV in various feedstuffs under a wide range of time and temperature conditions during storage using EhV as a surrogate. Corn- and soybean-based feed ingredients including corn, corn fermented protein, distiller dried grains with solubles, extruded soybean meal, high protein distiller’s grains, solvent-extracted soybean meal, soybean hulls, complete feed, and a positive control (no matrix) were inoculated with EhV (1 × 108 viruses/mL). Negative controls were inoculated with medium containing no EhV for each matrix. To assess the effects of different times and temperatures of storage, all samples were stored at temperatures of 4, 24, and 34 °C for 1, 5, 60, and 120 d. For each timepoint and temperature combination, samples were evaluated for virus presence (qPCR) and viability using a previously validated viability qPCR (v-qPCR) method. On average, we observed a 0.2 log reduction in viable viral DNA content over the 120-d period, with a 0.1 log reduction across varying temperatures. No reductions in EhV viability exceeding 1 log were detected for any matrix and the positive control at any time and temperature combination evaluated. No EhV was recovered from the negative control samples. Given that the experimental error was calculated to be within the range of 1 log, we concluded that storing EhV at 4, 24, or 34 °C for up to 120 d did not result in the inactivation of EhV in any of the ingredients, complete feed, or the control with no matrix. These results demonstrate that ASFV-like NCLDVs is extremely resilient and can maintain viability in various feed matrices during long-term storage and suggest that extending storage time alone may not be an effective mitigation practice against African swine fever virus.

Shenling Baizhu powder alleviates non-alcoholic fatty liver disease by modulating autophagy and energy metabolism in high-fat diet-induced rats

BackgroundNon-alcoholic fatty liver disease (NAFLD) has emerged as a burgeoning health problem worldwide, but no specific drug has been approved for its treatment. Shenling Baizhu powder (SL) is extensively used to treat NAFLD in Chinese clinical practice. However, the therapeutic components and pharmacological mechanisms of SL against NAFLD have not been thoroughly investigated. PurposeThis study aimed to investigate the pharmacological impact and molecular mechanism of SL on NAFLD. MethodsFirst, we established an animal model of NAFLD by high-fat diet (HFD) feeding, and evaluated the therapeutic efficacy of SL on NAFLD by physiological, biochemical, pathological, and body composition analysis. Next, the effect of SL on autophagic flow in NAFLD rats was evaluated by ultrastructure, immunofluorescence staining, and western blotting. Moreover, an integrated strategy of targeted energy metabolomics and network pharmacology was performed to characterize autophagy-related genes and explore the synergistic effects of SL active compounds. UPLC-MS/MS, molecular docking combined with in vivo and in vitro experiments were conducted to verify the key compounds and genes. Finally, a network was established among SL-herb-compound-genes-energy metabolites-NAFLD, which explains the complicated regulating mechanism of SL on NAFLD. ResultsWe discovered that SL decreased hepatic lipid accumulation, hepatic steatosis, and insulin resistance, and improved systemic metabolic disorders and pathological abnormalities. Subsequently, an integrated strategy of targeted energy metabolomics and network pharmacology identified quercetin, ellagic acid, kaempferol, formononetin, stigmasterol, isorhamnetin and luteolin as key compounds; catalase (CAT), AKT serine/threonine kinase 1 (AKT), nitric oxide synthase 3 (eNOS), NAD(P)H quinone dehydrogenase 1 (NQO1), heme oxygenase 1 (HO-1) and hypoxia-inducible factor 1 subunit alpha (HIF-1α) were identified as key genes; while nicotinamide adenine dinucleotide phosphate (NADP) and succinate emerged as key energy metabolites. Mechanistically, we revealed that SL may exert its anti-NAFLD effect by inducing autophagy activation and forming a comprehensive regulatory network involving key compounds, key genes, and key energy metabolites, ultimately alleviating oxidative stress, endoplasmic reticulum stress, and mitochondrial dysfunction. ConclusionOur study demonstrated the therapeutic effect of SL in NAFLD models, and establishes a basis for the development of potential products from SL plant materials for the treatment of NAFLD.

254 Effect of feeding high oleic soybean oil to finishing pigs on growth performance, carcass characteristics, and meat quality

Abstract The objective of this study was to evaluate the effects of dietary fat source and feeding duration on growth performance, carcass characteristics, and meat quality of finishing pigs. Finishing pigs [n = 450; 21 wk of age; initial body weight (BW) = 113.7 ± 8 kg] were housed in 90 pens and assigned to one of five dietary treatments in a 2 × 2 + 1 factorial design. Dietary treatments consisted of two fat sources (CWG: 4% inclusion of choice white grease and HOSO: 4% inclusion of high oleic soybean oil) each provided 2 or 4 wk before marketing. The “+1” diet was a corn-based diet without fat inclusion (CON). Observations included pig growth performance (on d 14 and d 28 of feeding), carcass characteristics (12 pigs per treatment at marketing), fatty acid profile in the loins and bellies, and a consumer sensory evaluation. Data were analyzed using PROC MIXED in SAS considering dietary treatment as a main effect, feeding duration, and their interactions. Contrast tests were used to compare dietary treatments with control group. From d 14 to 28 and overall experimental period (d 0–28), pigs fed fat-supplemented diets had a greater (P &amp;lt; 0.05) average daily gain and gain to feed ratio than CON fed pigs. There was no significant difference (P &amp;gt; 0.05) in growth performance when comparing fat sources or feeding periods. Pigs supplemented with either CWG or HOSO showed a tendency to have a greater (P &amp;lt; 0.1) belly weight and belly yield, and a lesser (P &amp;lt; 0.1) loin yield and loin muscle area when compared with CON pigs. Loins from the 2-wk period of fat supplementation had darker (Coloration l, P &amp;lt; 0.05) meat coloration when compared with 4 wk. The loin from pigs fed fat sources had greater (P &amp;lt; 0.05) concentration of oleic acid and eicosenoic acid when compared with CON. This improvement was mainly from HOSO. When CWG was compared with HOSO, pigs fed CWG had a greater (P &amp;lt; 0.05) concentration of palmitic acid and stearic acid while the HOSO pigs had a greater concentration of oleic acid and linolenic acid in the loin. In the belly, CON had greater (P &amp;lt; 0.05) concentration of palmitic acid and stearic acid while pigs fed fat sources had a greater concentration of oleic acid and eicosenoic acid. Bellies from HOSO had greater (P &amp;lt; 0.05) concentration of oleic acid and α-linolenic acid methyl ester while CWG had greater concentration of g-linolenic acid. As for the sensory evaluation, the palatability and acceptability of pork were not affected (P &amp;gt; 0.05) by dietary treatments. In conclusion, supplementation with HOSO not only improved performance but tended to improve some carcass characteristics and increased the concentration of oleic acid and some other unsaturated FAs with a concomitant decrease in the concentration of some saturated FAs in pork.

PSV-12 Microbial community structure of dairy cattle is stable through oscillating crude protein inclusion

Abstract Diet has an important role in shaping the structure of rumen microbial communities. However, little is known about the interaction between dietary crude protein (CP) level and CP feeding pattern on the rumen microbiome of dairy cows. Here, the objective was to evaluate the influence of CP level (low protein [LP], 13.8%; high protein [HP], 15.5% of dry matter [DM] basis) and CP feeding pattern (OF = oscillating, SF = static) on the composition and diversity of the rumen microbiome of lactating dairy cows using 16S rRNA gene amplicon sequencing. Rumen-cannulated Holstein cows (n = 8) in mid- to late-lactation were assigned to a 2 x 2 factorial experiment consisting of 4 experimental periods of 28 d. Each experimental period had an adaptation phase to the diet (24 d) and a sampling phase (d 25 to 28). The treatments with oscillating feeding alternated diets every 48 h to vary CP above and below the mean CP level (OF-LP = 13.8 ± 1.8%; OF-HP = 15.5 ± 1.8% CP of DM) whereas diets were constant in the static feeding (SF-LP = 13.8%; SF-HP = 15.5% CP of DM). According to the NASEM (2021) model predictions the LP diet supplied 94% of the microbial protein requirement while the HP diet exceeded (104%) requirement. Rumen samples were collected 4 h after feeding through a rumen cannula and amplicon libraries were generated targeting the V4 region of the 16S rRNA gene. The amplicon sequences were analyzed in qiime2. Sequences where trimmed based on their quality and then grouped in ASVs using DADA2. The ASVs were used to analyze the composition and diversity of the rumen microbiome in each treatment. Alpha diversity of the rumen microbiome did not change across treatments (Kruskal Wallis, P &amp;gt; 0.05), but Pielou’s evenness increased by 0.01 units (Kruskal Wallis, P = 0.04). These results support the hypothesis that the rumen microbiome is stable to oscillating CP feeding patterns and compensates for the changes in crude protein content in the diet. Further research is required to understand the dynamics of this compensation and what other metabolic processes in the ruminant contribute to maintaining production under an oscillating diet.

248 Effects of feeding finishing pig diets differing in Ca:P ratio, added phytase and 25(OH)D3 on growth performance, serum 25(OH)D3, carcass characteristics, and bone characteristics

Abstract A total of 2,160 pigs [337 × 1050, PIC; initial body weight (BW) = 33.2 ± 1.4 kg] were used in a 114-d trial to determine the effects of feeding diets differing in Ca:P ratio and added phytase or phytase and 25(OH)D3 (Hy-D, DM Nutritional Products, Parsippany, NJ) on growth performance, carcass characteristics, serum 25(OH)D3, and bone characteristics. Pigs were housed in mixed sex pens with 27 pigs per pen and 20 pens per treatment. The four treatments were assigned to pens in a randomized complete block design and consisted of 1) a high phosphorus (HP) diet with standardized total tract digestibility (STTD) P at 115% of NRC (2012) requirement estimate without added phytase and formulated to a 1.25:1 Ca to P ratio; 2) low phosphorus (LP) diet with STTD P at 80% of NRC requirement without added phytase and formulated to a 1.25:1 Ca to P ratio; 3) HP with phytase (HP+phytase) diet with STTD P at 115% of NRC requirement using 0.125% STTD P release from 600 FYT/kg HiPhorius and 1.1:1 Ca to P ratio; and 4) Diet 3 except 25(OH)D3 replaced most of the vitamin D3 in the diet (HP+25(OH)D3). Diets were fed in 4 phases from 32 to 50, 50 to 75, 75 to 100, and 100 to 133 kg. For overall growth performance, source of vitamin D had no impact on performance. Pigs fed HP diets had improved (P &amp;lt; 0.05) average daily gain (ADG), average daily feed intake (ADFI) and gain to feed ratio (G:F) compared with those fed LP diets, and increased ADFI compared with those fed the HP+phytase diets (Table 1). For 25(OH)D3 measured on d 50, pigs fed the HP diets had increased (P &amp;lt; 0.05) serum 25(OH)D3 compared with pigs fed the LP diets and pigs fed the HP+25(OH)D3 diets had increased (P &amp;lt; 0.05) serum 25(OH)D3 compared with pigs fed the HP+phytase diets. Pigs fed the HP diets had greater (P &amp;lt; 0.05) HCW and percentage lean than those fed LP diets. For bone analysis, pigs fed HP diets had greater (P &amp;lt; 0.05) bone ash (g) and breaking strength than pigs fed LP or HP+phytase and 1.1:1 Ca to P ratio. In conclusion, compared with pigs fed LP diets, HP-fed pigs had improved performance and HCW. Dietary 25(OH)D3 replacing D3 did not impact performance but increased circulating 25(OH)D3.

12 Effects of increasing SID lysine (Lys) and metabolizable energy (ME) levels of lactation diets fed to young and multiparous sows

Abstract Providing insufficient lysine to lactating sows can reduce piglet performance and subsequent farrowing performance of sows. Current SID lysine and ME recommendations for lactating sows are approximately 60 g/d and 20 Mcal/d, respectively. Because of variations in feed intake during lactation, a portion of sows do not meet recommended Lys intake levels. There is no clear understanding of the Lys:Calorie ratio when dietary energy is increased in the summer to ensure adequate caloric intake. The objective was to evaluate a potential advantage of feeding diets with SID Lys and energy levels that exceed recommendations to lactating sows. A total of 855 sows were fed during the summer of 2023 in 2×2 factorial arrangement of treatments in a randomized complete block design. Factors included SID lysine [low (0.85%) vs high (1.11%)] and ME [low (3,183 kcal/kg) vs high (3,334 kcal/kg)]. Diets were formulated to deliver 61 g of SID lysine at 0.85% inclusion to sows that consume 7.2 kg of complete feed per day. Primary outcome variables were sow body composition, lactation average daily feed intake (ADFI), average piglet weaning weight, and pre-wean mortality. There were no interactions between treatments (P &amp;gt; 0.05). SID Lys intake was 61.2 and 76.4 g/d for low and high Lys, respectively (P &amp;lt; 0.01). ME intake was 21.9 and 23.4 Mcal/d for low and high energy, respectively (P &amp;lt; 0.01). Contrary to expectations, ADFI did not differ (P = 0.25) between sows fed the low- and high-energy diets, however, sows fed low lysine consumed 0.29 kg more feed (P &amp;lt; 0.01) per day compared with sows fed high lysine. There were no differences (P ≥ 0.70) in the number of piglets born alive for any treatment group. Sows fed high energy had 0.27 fewer (P &amp;lt; 0.01) still-born piglets per litter compared with sows fed low energy. Pre-wean mortality was also reduced (P = 0.05) by 0.76 percentage units in litters of sows fed the high-energy diet compared with litters of sows fed the low energy. Lysine level had no effects on farrowing and litter performance (P &amp;gt; 0.05). Litters from sows fed the high-energy diet gained 1.2 kg more (P = 0.05) body weight during lactation and tended to result in litter-weaned weights that were 1.5 kg heavier (P = 0.06) than litters from sows fed the low-energy diet. Feeding a diet with a greater lysine concentration during lactation reduced feed intake but did not affect litter performance. In contrast, increasing dietary energy immediately before farrowing and during lactation did not affect sow feed intake but reduced pre-wean mortality and resulted in fewer still-born piglets, greater litter gains, and heavier litter weaning weights.

136 Effects of acid-binding capacity in low-zinc diets on growth performance of weaned pigs

Abstract Post-weaning diarrhea (PWD) of piglets remains a concern in the pork industry. Historically, PWD has been controlled with dietary solutions such as antibiotics as growth promotors and high dietary inclusion of ZnO. However, such use of antibiotics is not permitted any longer and such use of ZnO has already been banned in the EU. In the present trial, the objective was to study the effects on growth performance of acid binding capacity (ABC) as dietary solution in low zinc diets compared to control diet with high zinc. In total, 1,445 pigs (Camborough F1 female x 800 boar line; PIC Canada) were weaned at 20 ± 1 d of age, comprising of equal number of gilts and barrows, and were randomly placed into one of 50 mixed-gender pens (50% barrows and 50% gilts) in two rooms filled four d apart, for 28 or 29 pigs per pen. In total, five dietary regimes were tested during Phase 1 (d 0-7) and 2 (d 7-21): one high in Zn (2,000-3,000 ppm ZnO; 412 mEq/kg ABC-4) and 4 low in Zn (150 ppm) with incremental reductions in ABC-4 from 326 to 150 mEq/kg. Reductions in ABC-4 were accomplished using a combination of changes; added organic acids (formic, fumaric, benzoic), Ca formate to replace limestone, and a low ABC-4 soy protein concentrate to replace regular soy protein concentrate. Pigs were fed a common diet during Phase 3 (d 21-42). For each feeding phase all diets were formulated to equal net energy and standardized ileal digestible amino acids and contained phytase. At d 21, pigs fed high Zn were 1.6 kg heavier (11.3 vs 9.7 kg; P &amp;lt; 0.01) than pigs fed low Zn with greatest ABC-4. Within low Zn diets, reducing ABC-4 linearly increased body weight (BW; 9.7 vs. 10.1 kg). These differences continued until d 42: pigs fed high Zn were 1.8 kg heavier (24.1 vs 22.3 kg; P &amp;lt; 0.01) than pigs fed low Zn with greatest ABC-4). Within low Zn diets, reducing ABC-4 for the first 3 wk after weaning linearly increased BW (22.9 vs. 22.3 kg; P &amp;lt; 0.01). This increased growth was caused by a combination of increased (P &amp;lt; 0.01) feed intake and increased (P &amp;lt; 0.05) gain-to-feed and coincided with reduced (P &amp;lt; 0.01) incidence of scours. In conclusion, weaned pigs fed high Zn diets grew more than pigs fed low Zn diets. Dietary ABC-4 is a dietary solution to consider for ameliorating the reduced growth by pigs fed low Zn diets: 33% of the reduced growth could be compensated for by feeding diets low in dietary ABC-4 during the first 3 wk after weaning.

The prostaglandin E2 EP3 receptor has disparate effects on islet insulin secretion and content in β-cells in a high-fat diet-induced mouse model of obesity.

Signaling through prostaglandin E2 EP3 receptor (EP3) actively contributes to the β-cell dysfunction of type 2 diabetes (T2D). In T2D models, full-body EP3 knockout mice have a significantly worse metabolic phenotype than wild-type controls due to hyperphagia and severe insulin resistance resulting from loss of EP3 in extra-pancreatic tissues, masking any potential beneficial effects of EP3 loss in the β cell. We hypothesized β-cell-specific EP3 knockout (EP3 βKO) mice would be protected from high-fat diet (HFD)-induced glucose intolerance, phenocopying mice lacking the EP3 effector, Gαz, which is much more limited in its tissue distribution. When fed a HFD for 16 wk, though, EP3 βKO mice were partially, but not fully, protected from glucose intolerance. In addition, exendin-4, an analog of the incretin hormone, glucagon-like peptide 1, more strongly potentiated glucose-stimulated insulin secretion in islets from both control diet- and HFD-fed EP3 βKO mice as compared with wild-type controls, with no effect of β-cell-specific EP3 loss on islet insulin content or markers of replication and survival. However, after 26 wk of diet feeding, islets from both control diet- and HFD-fed EP3 βKO mice secreted significantly less insulin as a percent of content in response to stimulatory glucose, with or without exendin-4, with elevated total insulin content unrelated to markers of β-cell replication and survival, revealing severe β-cell dysfunction. Our results suggest that EP3 serves a critical role in temporally regulating β-cell function along the progression to T2D and that there exist Gαz-independent mechanisms behind its effects.NEW & NOTEWORTHY The EP3 receptor is a strong inhibitor of β-cell function and replication, suggesting it as a potential therapeutic target for the disease. Yet, EP3 has protective roles in extrapancreatic tissues. To address this, we designed β-cell-specific EP3 knockout mice and subjected them to high-fat diet feeding to induce glucose intolerance. The negative metabolic phenotype of full-body knockout mice was ablated, and EP3 loss improved glucose tolerance, with converse effects on islet insulin secretion and content.

Abstract 2069: Impact Of Endothelial Stiffening And CD36-mediated Lipid Uptake On Atherosclerotic Lesion Formation

Objective: To determine the impact of endothelial stiffening induced by CD36 (cluster of differentiation 36) lipid uptake in the development of atherosclerosis. Approach and Results: Endothelial stiffening of intact en face monolayers, as assessed by atomic force microscopy, reveal the hyperlipidemic mouse model of atherosclerosis, LDLR -/- (low density lipoprotein receptor knockout) is significantly stiffer, especially in the atheroprone aortic arch, as compared to wild type controls (n=4 male mice with 8-15 tissue measurement sites per condition per mouse, p&lt;0.05). Furthermore, a 4-5 month high fat diet (HFD) feeding in LDLR -/- mice resulted in significantly enhanced stiffening compared to regular chow feeding, an effect that was observed in males but not females (n=6-8 mice, p&lt;0.05). There was a significantly greater plaque development, as analyzed using Oil O Red staining for lipids, in male HFD-fed LDLR -/- mice, as compared to age-matched females (n=5-6, p&lt;0.05). No significant difference between males and females was found in lipid panel parameters (n=4-6) or weight gain (n=10-14). Specific downregulation of CD36 in male hypercholesterolemic Cdh5.CreERT2CD36fl/fl LDLR -/- mice led to both a significant decrease in endothelial stiffening (n=5 mice, p&lt;0.05) and in the areas of atherosclerotic lesion formation (n=5-6 mice, p&lt;0.05). Mechanistically, we show that the saturated fatty acid, palmitic acid, increased endothelial stiffening in the en face monolayers of wild type mice, an effect which is prevented by the pre-treatment of the CD36 irreversible inhibitor, SSO (sulfo-N-succinimidyl oleate, n=5-6 male mice, p&lt;0.05). Conclusions: These results highlight that endothelial stiffness from intact aortas and atherosclerotic plaque formation following HFD feeding is strongly dependent on endothelial CD36.

Abstract 2070: Myeloid Smyd2 Deficiency Exacerbates Atherosclerosis Via Promoting Plaque Necrosis And Calcification

Introduction: The accumulation of lipoprotein-laden macrophages within arterial walls marks the earliest phase of atherosclerotic cardiovascular disease, giving rise to foam cells. Here, we aim to define the previously unexplored role of myeloid specific SMYD2 (a histone lysine methyltransferase) in atherosclerosis and plaque formation. Methods: Myeloid-specific Smyd2 knockout mice in ApoE -/- background (Smyd2 mKO ApoE -/- ) and their littermate controls (Smyd2 fl/fl ApoE -/- ) were subjected to Western diet (WD) feeding for up to 26 weeks. Atherosclerotic plaque distribution was examined by en-face Oil Red O (ORO) staining of freshly collected aortas. Hematoxylin &amp; Eosin (H&amp;E) staining on brachiocephalic artery (BCA) tissues were performed to determine total plaque size, lipid pool area, and necrotic core area. Plaque calcification was determined by von Kossa staining and Alizarin Red S staining. Primary bone marrow derived macrophages (BMDMs) isolated from Smyd2 fl/fl ApoE -/- and Smyd2 mKO ApoE -/- mice and cultured RAW 246.7 cells (with Smyd2 knock-down) were used for in vitro studies including calcification assay, PR-PCR, and Western blot analysis. Results: Myeloid Smyd2 deficient mice demonstrated significantly increased aortic plaque burden on ORO staining as compared to control mice following WD feeding, though with slower WD-induced body weight gain relative to Smyd2 fl/fl ApoE -/- control mice. H&amp;E staining of BCA indicated that there was significant reduction in total lumen and lipid core area, while significantly increased total plaque and necrotic core in Smyd2 mKO ApoE -/- mice. Myeloid Smyd2 deletion promotes plaque calcification in mice fed with WD, and in cultured BMDMs and RAW 246.7 cells treated with calcification promoting media. Gene expression analysis of key calcification factors of aortic tissues and cultured cells showed significant upregulation of Sox9 and Msx2 genes in aortas of WD-fed Smyd2 mKO ApoE -/- mice and cultured Smyd2 deficient cells, as compared to controls. Conclusion: We delineated the consequences of Smyd2 deficiency in macrophages on atherosclerotic plaque development, particularly its impact on plaque necrosis and calcification.

The type of fatty acid dictates their impact on gut permeability and nutrient absorption

We showed that short- and long-term (3 to 12 weeks) high-fat diet (HFD) feeding reduced protein expression of nutrient transporters in the proximal jejunum of mice. The most abundant fatty acids (FA) in HFD were oleic (OA), palmitic (PA) and stearic (EA) acid. Because PA and EA are generally regarded as pro-inflammatory, we hypothesize that dietary PA and EA alter gut permeability and absorption via inflammatory activation. To test this hypothesis, we orally administered HFD-matched doses of OA, PA, and EA to male C57BL/6 mice, fed on purified diet control (LFD), for 3 weeks. Food intake and body weight were monitored, and composition were also evaluated. We next qPCR-assessed the mRNA expression of cytokines ( TNF-α, IL-6, IL-1β, IFN-γ, IL-10) and inflammatory signaling transducers ( MD-2 and Myd88) as well as the protein content of nutrient transporters (Glut2, Pept1, Fat/cd36 and Npc1l1) and cell-cell adhesion proteins (Occludin) in the gut. Small intestinal permeability was assessed ex vivo and gut morphology was histologically determined. In addition, Caco-2 enterocytes were used to assess the impact of specific cytokines on nutrient transport and gut barrier integrity. All dietary FA reduced food intake without affecting lean or fat mass. In the jejunum, OA increased TNF-α gene expression whereas PA upregulated IFN-γ and MD-2 gene expression. Furthermore, OA reduced the nutrient transporters Glut2, Pept1, and Fat/cd36 without affecting Npc1l1, whereas PA and EA reduced Occludin protein content. PA, but not OA and EA, increased jejunum paracellular permeability ex vivo and increased villus length. In Caco-2 cells, while Tnf-α did not affect Glut2, Pept1 and Fat/cd36 or Npc1l1 content, Ifn-γ downregulated Occludin protein content. We conclude that OA and, more potently, PA exert inflammatory effects which contribute to damage gut barrier integrity and downregulate nutrient absorption. Our data point to IFN-γ as a main player coupling dietary stress from PA to altered gut homeostasis. Funding: FAPESP (grants number: 2014/12871-9, 2019/05086-7, 2020/12201-4, and 2022/14545). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Reoxygenation Mitigates Intermittent Hypoxia-Induced Systemic Inflammation and Gut Microbiota Dysbiosis in High-Fat Diet-Induced Obese Rats.

Obstructive sleep apnea (OSA) is a prevalent sleep breathing disorder characterized by intermittent hypoxia (IH), with continuous positive airway pressure (CPAP) as its standard treatment. However, the effects of intermittent hypoxia/reoxygenation (IH/R) on weight regulation in obesity and its underlying mechanism remain unclear. Gut microbiota has gained attention for its strong association with various diseases. This study aims to explore the combined influence of IH and obesity on gut microbiota and to investigate the impact of reoxygenation on IH-induced alterations. Diet-induced obese (DIO) rats were created by 8-week high-fat diet (HFD) feeding and randomly assigned into three groups (n=15 per group): normoxia (NM), IH (6% O2, 30 cycles/h, 8 h/day, 4 weeks), or hypoxia/reoxygenation (HR, 2-week IH followed by 2-week reoxygenation) management. After modeling and exposure, body weight and biochemical indicators were measured, and fecal samples were collected for 16S rRNA sequencing. DIO rats in the IH group showed increased weight gain (p=0.0016) and elevated systemic inflammation, including IL-6 (p=0.0070) and leptin (p=0.0004). Moreover, IH rats exhibited greater microbial diversity (p<0.0167), and significant alterations in the microbial structure (p=0.014), notably the order Clostridiales, accompanied by an upregulation of bile acid metabolism predicted pathway (p=0.0043). Reoxygenation not only improved IH-exacerbated obesity, systemic inflammation, leptin resistance, and sympathetic activation, but also showed the potential to restore IH-induced microbial alterations. Elevated leptin levels were associated with Ruminococcaceae (p=0.0008) and Clostridiales (p=0.0019), while body weight was linked to Blautia producta (p=0.0377). Additionally, the abundance of Lactobacillus was negatively correlated with leptin levels (p=0.0006) and weight (p=0.0339). IH leads to gut dysbiosis and metabolic disorders, while reoxygenation therapy demonstrates a potentially protective effect by restoring gut homeostasis and mitigating inflammation. It highlights the potential benefits of CPAP in reducing metabolic risk among obese patients with OSA.

The ketogenic diet does not improve cardiac function and blunts glucose oxidation in ischaemic heart failure.

Cardiac energy metabolism is perturbed in ischaemic heart failure and is characterized by a shift from mitochondrial oxidative metabolism to glycolysis. Notably, the failing heart relies more on ketones for energy than a healthy heart, an adaptive mechanism that improves the energy-starved status of the failing heart. However, whether this can be implemented therapeutically remains unknown. Therefore, our aim was to determine if increasing ketone delivery to the heart via a ketogenic diet can improve the outcomes of heart failure. C57BL/6J male mice underwent either a sham surgery or permanent left anterior descending coronary artery ligation surgery to induce heart failure. After 2 weeks, mice were then treated with either a control diet or a ketogenic diet for 3 weeks. Transthoracic echocardiography was then carried out to assess in vivo cardiac function and structure. Finally, isolated working hearts from these mice were perfused with appropriately 3H or 14C labelled glucose (5 mM), palmitate (0.8 mM), and β-hydroxybutyrate (β-OHB) (0.6 mM) to assess mitochondrial oxidative metabolism and glycolysis. Mice with heart failure exhibited a 56% drop in ejection fraction, which was not improved with a ketogenic diet feeding. Interestingly, mice fed a ketogenic diet had marked decreases in cardiac glucose oxidation rates. Despite increasing blood ketone levels, cardiac ketone oxidation rates did not increase, probably due to a decreased expression of key ketone oxidation enzymes. Furthermore, in mice on the ketogenic diet, no increase in overall cardiac energy production was observed, and instead, there was a shift to an increased reliance on fatty acid oxidation as a source of cardiac energy production. This resulted in a decrease in cardiac efficiency in heart failure mice fed a ketogenic diet. We conclude that the ketogenic diet does not improve heart function in failing hearts, due to ketogenic diet-induced excessive fatty acid oxidation in the ischaemic heart and a decrease in insulin-stimulated glucose oxidation.

Abstract 158: The Role Of Ehbp1 In Hypercholesterolemia

Background: Despite aggressive lowering of cholesterol, conventional lipid-lowering therapies only modestly lower cardiovascular risk in the population. Therefore, identifying novel hypercholesterolemia-risk targets is of critical importance. Human genome-wide association studies (GWAS) have revealed that several single-nucleotide polymorphisms (SNPs) in EHBP1 , the gene that encodes EH domain binding protein 1 (EHBP1), an endocytic trafficking regulator, are associated with serum cholesterol. However, the mechanisms underlying this association and the role of EHBP1 in cholesterol metabolism are unknown. We hypothesize that EHBP1 is a novel hypercholesterolemia risk factor. The goal of this study is to explore the role of EHBP1 in hypercholesterolemia and its underlying mechanisms. Methods: Hepatocyte EHBP1 was silenced by intravenous injection (IV) of AAV8-H1-shEhbp1 in wild-type (WT), Apoe-/- and Ldlr-/- mice, followed by Western Diet feeding to induce hypercholesterolemia and atherosclerosis. Primary murine and human hepatocytes were isolated for in vitro mechanistic studies. We also leveraged publicly available human genetic studies and unbiased scRNA datasets to support our study. Results: Individuals with the EHBP1 rs10496099 T&gt;C variant have decreased serum cholesterol and reduced liver EHBP1 expression. Consistent with the human data, our in vivo study with hypercholesterolemic mice shows that EHBP1 silencing in hepatocytes decreases plasma total and LDL/VLDL cholesterol. Our in vitro study with primary hepatocytes reveals that EHBP1 deficiency eliminates sortilin (SORT1)-mediated PCSK9 secretion and induces LDLR-mediated LDL uptake. Mechanistically, we found that EHBP1 silencing abolishes the homeostasis of the retromer complex, a protein complex that helps retrograde and stabilize sortilin. Conclusion: Hepatocyte EHBP1 promotes sortilin-mediated PCSK9 secretion by maintaining retromer homeostasis, leading to LDLR degradation and hypercholesterolemia. Our study elucidates a novel link between EHBP1 and other cholesterol-associated loci (e.g., SORT1 , PCSK9 , and LDLR) and provides new mechanistic insight into the role of EHBP1 in hepatic cholesterol metabolism and hypercholesterolemia.