Evaluating the Influence of Different Recommended Dietary Levels of Cu and Zn on Finishing Pigs

This study was conducted to evaluate the effects of dietary supplementation of different recommended levels of Cu and Zn on antioxidant capacity, tissue mineral status, minerals excretion, meat quality, digestive enzyme activity, and metal transporters in finishing pigs. A total of 120 pigs (with an average initial body weight (BW) of 70.0 ± 2.1 kg) were randomly divided into four treatments: (1) basal diet without added Cu or Zn (control), (2) basal diet+35 mg cupreous N-carbamylglutamate chelate (NCG-Cu) +150 mg zinc-methionine chelate (Zn-Met) (AC), (3) basal diet + 3.0 mg of NCG-Cu + 43 mg Zn-Met (CN), and (4) basal diet + 3.5 mg NCG-Cu + 50 mg Zn-Met (NRC100). Pig growth performance was not affected by the level of Cu or Zn. Among the four treatments, the AC treatment had the highest concentration (P < 0.05) of glutathione peroxidase (GSH-Px). Pigs fed the AC diet had the highest (P < 0.05) liver Zn, fecal Cu, and fecal Zn among the four treatments. The protein levels of trypsin and aminopeptidase N (APN) in the intestinal mucosa showed their highest levels (P < 0.05) in the NRC100 and AC treatments. The mRNA levels of trypsinogen and APN were significantly up-regulated (P < 0.05) in the AC, CN, and NRC100 treatments compared with the control. The mRNA levels for the Zn transporter genes SLC30A1 (ZnT1) and SLC30A2 (ZnT2) were significantly up-regulated (P < 0.05) in the AC treatment, and the mRNA levels for SLC39A4 (ZIP4) and metallothionein 1 (MT) in the AC, CN, and NRC100 treatments were significantly up-regulated (P < 0.05) compared with the control. Meat quality were not affected (P > 0.05) by the different recommended levels of Cu and Zn. These results indicated that the supplemental Cu and Zn levels routinely used in AC diets in Chinese commercial feed enterprises should be reduced.

Resveratrol Alleviates Oxidative Stress Induced by Oxidized Soybean Oils and Improves Gut Function via Changing Gut Microbiota in Weaned Piglets

Background: The objective of this study was to investigate the effects of dietary resveratrol supplementation on growth performance, redox status, inflammatory state, and intestinal function of weaned piglets fed oxidized soybean oils.Methods: A total of twenty-eight castrated weaned male piglets with a similar body weight of 10.19 ±1 kg were randomly assigned to 4 dietary treatments for 28 days feeding trial with 7 replications per treatment and 1 piglet per replicate. Treatments were arranged as a 2×2 factorial with oil type [fresh soybean oils (FSOs) vs. oxidized soybean oils (OSOs)] and dietary resveratrol (RES) (0 vs. 300 mg/kg).Result: Inclusion of OSOs decreased the villus/crypt ratio (VCR), while the villus height (VH) and VCR in the jejunum of weaned piglets was increased by dietary RES (P< 0.05). The activities of lipase, chymotrypsin, and lactase were decreased by OSOs, however dietary RES supplementation increased the activities of lipase, chymotrypsin, lactase, and α-amylase in the jejunum of weaned piglets (P< 0.05). Dietary RES increased the apparent digestibility of crude fat (EE). Dietary RES supplementation in the diets supplemented with OSOs decreased the level of interleukin-1β (IL-1β), interleukin-6 (IL-6), interleukin-8 (IL-8), and tumor necrosis factor-α (TNF-α) in the plasma of weaned piglets, but failed to influence the IL-1β, IL-6, IL-8, and TNF-α level when diets supplemented with FSOs. Dietary RES alleviated the decrease of total-superoxide dismutase activity in the plasma of weaned piglets fed OSOs (P< 0.05). Dietary supplemented with OSOs and RES decreased the level of H2O2 in the plasma of weaned piglets (P< 0.05). RES alleviates the intestinal barrier damage fed OSOs in weaned piglets by increasing the mRNA expression of ZO-1 and Occludin. It is noteworthy that inclusion of OSOs in diets increased the abundance of Actinobacteria, and decreased the abundance of Tenercutes (P< 0.05). RES increased the abundance of Firmicutes, and decreased the abundance of Bacteroidetes (P< 0.05). At the genus level, RES decreased the abundance of Prevotella-1, Prevotellaceae UCG003, and Clostridium_sensu_stricto_6 in the colon. OSOs decreased the level of acetic acid, and dietary RES increased the level of acetic acid and butyric acid in the colon of weaned piglets.Conclusions: Dietary RES supplementation improved the villus-crypt structure, digestive enzyme activities and alleviated OSOs induced digestive absorption disorder. In addition, RES may alleviate OSOs immune status and energy metabolism of weaned piglets by affecting gut microbiota and its metabolite SCFAs. Notably, this positive effect of RES on OSOs may be related to decrease in the abundance of Prevotella_1 and Prevotellaceae_UCG-003.

Single-Cell Ribonucleic Acid Sequencing Clarifies Cold Tolerance Mechanisms in the Pacific White Shrimp (Litopenaeus Vannamei)

To characterize the cold tolerance mechanism of the Pacific white shrimp (Litopenaeus vannamei), we performed single-cell RNA sequencing (scRNA-seq) of ∼5185 hepatopancreas cells from cold-tolerant (Lv-T) and common (Lv-C) L. vannamei at preferred and low temperatures (28°C and 10°C, respectively). The cells fell into 10 clusters and 4 cell types: embryonic, resorptive, blister-like, and fibrillar. We identified differentially expressed genes between Lv-T and Lv-C, which were mainly associated with the terms “immune system,” “cytoskeleton,” “antioxidant system,” “digestive enzyme,” and “detoxification,” as well as the pathways “metabolic pathways of oxidative phosphorylation,” “metabolism of xenobiotics by cytochrome P450,” “chemical carcinogenesis,” “drug metabolism-cytochrome P450,” and “fatty acid metabolism.” Reconstruction of fibrillar cell trajectories showed that, under low temperature stress, hepatopancreas cells had two distinct fates, cell fate 1 and cell fate 2. Cell fate 1 was mainly involved in signal transduction and sensory organ development. Cell fate 2 was mainly involved in metabolic processes. This study preliminarily clarifies the molecular mechanisms underlying cold tolerance in L. vannamei, which will be useful for the breeding of shrimp with greater cold tolerance.

Effects of Restricted Feeding on Growth Performance, Intestinal Immunity, and Skeletal Muscle Development in New Zealand Rabbits

This study aimed to explore the effects of different feeding restriction levels on the growth performance, intestinal immunity, and skeletal muscle development of meat rabbits. Additionally, we studied whether complete compensatory growth could be obtained post 2 weeks of restricted feeding, in order to seek a scientific mode of feeding restriction. Each of three groups was exposed to 3 weeks of feeding restriction and 2 weeks of compensatory growth. The 15% feeding restriction showed a negligible effect on the final body-weight of the rabbits (p > 0.05), but significantly reduced the feed-to-weight ratio (p < 0.05); reduced diarrhea and mortality; and increased digestive enzyme activity and antioxidant capacity. However, a 30% feeding-restriction level substantially reduced the growth rate of the rabbits (p < 0.05), impaired skeletal muscle development, and showed no compensatory growth after 2 weeks of nutritional recovery. Additionally, immunoglobulin and antioxidant enzyme synthesis were impaired due to reduced nutritional levels, and levels of pro-inflammatory factors were increased during the compensation period. The IGF1 mRNA expression decreased significantly (p < 0.05), whereas MSTN and FOXO1 expression increased noticeably (p < 0.05). Moreover, protein levels of p-Akt and p-p70 decreased significantly in the 15% feeding restriction group. Overall, the 15% feeding limit unaffected the weight and skeletal muscle development of rabbits, whereas the 30% feeding limit affected the growth and development of skeletal muscle in growing rabbits. The PI3K/Akt signaling pathway is plausibly a mediator of this process.

A New Practice to Monitor the Fabrication Process of Fab-Targeting Ligands from Bevacizumab by LC-MS: Preparation and Analytical Characterization

The objective of this study was to qualitatively evaluate a Fab-targeting ligand preparation containing free thiol groups in the hinge region by using bevacizumab as a model. The evaluation focused on the purification of fragments through a nonaffinity-based process using a centrifugal ultrafiltration technique and mild reduction conditions for the intact production of F(ab’) fragments with specific inter-heavy-chain disulfide bonds cleavage. Under these conditions, F(ab’) fragments with a defined chemical composition were successfully obtained via proteolytic digestion followed by a controlled reduction reaction process maintaining the integrity of the binding sites. The ultrafiltration purification technique appears to be suitable for the removal of the digestive enzyme but inefficient for the removal of Fc fragments, thus requiring additional processing. A suitable analytical strategy was developed, allowing us to demonstrate the reformation of disulfide bridges between the two reduced cysteines within F(ab’) fragments.