Phosphorus nutrition of growing pigs

Dose of phytase from either Aspergillus niger or Escherichia coli on performance of nursery piglets

Supplementing swine diets with phytase increases phosphorus release by approximately 50% from cereal phytates. The increase in phosphorus availability allows for a reduction in dietary phosphorus supplementation from mineral sources and decreases the environmental impact of pork production through a decrease in phosphorus excretion. Superdosing phytase has been reported to boost swine productivity, improve the digestibility of other nutrients, and mitigate the antinutritional effects of phytates. However, there are significant cost differences among phytase products. Bacterial phytases are considered more modern, often with a higher cost of inclusion. A study was conducted with 288 piglets that were 21 d of age and weighed 6.43 ± 0.956 kg. Pigs were divided into four groups. Each group of pigs was fed a different experimental diet varying in phytase source and level: fungal phytase (Aspergillus niger) at 500 FTU/kg of diet, fungal phytase at 2,000 FTU/kg, bacterial phytase (Escherichia coli) at 500 FTU/kg, and bacterial phytase at 2,000 FTU/kg. No differences were found for phytase sources or doses on productivity at 14 and 21 d postweaning. However, piglets supplemented with 2,000 FTUs/kg of phytase in the diet during the first 21 d of nursery exhibited a 5.8% better feed conversion (P = 0.02). An interaction between phytase source and dose was observed for average live weight and daily weight gain over the 42-d nursery period (P < 0.05). Supplementing the diet with 2,000 FTU/kg of fungal phytase improved daily weight gain and live weight throughout the experimental period compared to piglets supplemented with 500 FTU/kg of the same phytase source. Additionally, it resulted in better final weights compared to piglets supplemented with 500 FTU/kg of bacterial phytase. Phytase inclusion at 2,000 FTU/kg improved feed conversion by 2.07% over the 42-d nursery period. The most economically favorable feed conversion ratios were observed when supplementing the diet with fungal phytase at 2,000 FTUs/kg.

Dietary complex probiotic supplementation changed the composition of intestinal short-chain fatty acids and improved the average daily gain of weaned piglets

Probiotics are a group of active microorganisms that form colonies within the body and alter the composition of the flora in a specific area to provide benefits to the host. In this study, a total of 96 Duroc × Landrace × Yorkshire weaned piglets with an initial body weight (BW) of 8.56 ± 0.53 kg were employed in a randomized complete block design for a 28-day experiment. Pigs were randomly divided into two treatment groups: the control group (CON) and the complex probiotic group (CON + 0.2% probiotics), respectively. The study found that through the 28-day experiment, the average daily gain (ADG) of the complex probiotic group was significantly higher than that of the CON (p < 0.05). However, compared with the CON, the feed conversion efficiency significantly decreased on days 0-14 (p < 0.05). The addition of dietary complex probiotic significantly increased the villus height (VH) of duodenum and ileum, acetate, propionate, butyrate, and total short-chain fatty acids (SCFAs) in feces, and decreased fecal methyl mercaptans, acetic acid, and CO2 (p < 0.05). It concluded that feeding weaned piglets 0.2% complex probiotic increased the VH of duodenum and ileum, as well as changed the content of SCFAs in feces. This ultimately led to an increase in ADG.

A New Biosynthetic 6-Phytase Added at 500 Phytase Unit/kg Diet Improves Growth Performance, Bone Mineralization, and Nutrient Digestibility and Retention in Weaned Piglets and Growing-Finishing Pigs

Two experiments were performed to evaluate the effect of a biosynthetic 6-phytase added at 500 phytase unit (FTU)/kg diet on growth performance, bone mineralization, and nutrient digestibility and retention in weaned piglets and growing-finishing pigs. Experiments were performed on 90 weaned male and female piglets with an average initial body weight (BW) at 7.7 ± 0.73 kg, 26 days of age) and 300 male and female growing pigs (initial BW: 21.0 ± 3.44 kg) for 43 and 98 days in experiments 1 and 2, respectively. In each experiment, the animals were assigned to one of three treatments according to a randomized complete block design. The treatments consisted of a positive-control (PC) diet formulated to meet nutrient requirements; a negative-control (NC) diet reduced similarly in calcium (Ca) and digestible P by 0.15 and 0.12% points in phases 1 and 2, respectively, in piglets and by 0.14, 0.11, and 0.10% points, respectively, in phases 1, 2, and 3 in growing-finishing pigs, compared with PC diet; and a NC diet supplemented with the new 6-phytase at 500 FTU/kg diet (PHY). The dietary P and Ca depletion reduced (p < 0.05) the final BW (-11.9%; -7.8%,), average daily gain (ADG, -17.8%; -10.1%), average daily feed intake (ADFI, -9.9%; -6.0%), gain-to-feed (G:F) ratio (-8.9%; -4.6%), and apparent total tract digestibility (ATTD) of P (-7.7% points; -6.7% points) in nursery piglets and growing pigs, respectively. It also decreased (p < 0.001) P and Ca retention by 6.1 and 9.4% points, respectively, in nursery pigs and ash, P, and Ca contents in metacarpal bones by 18.4, 18.4, and 16.8%, respectively, in growing pigs. Compared to animals fed the NC diet, phytase supplementation improved (p < 0.001) the final BW (+7.7%; +11.3%), ADG (+12.5%; +15.0%), G:F ratio (+8.4%; +5.8%), ATTD of Ca (+10.8% points; +7.2% points), and ATTD of P (+18.7% points; +16.6% points) in weaned piglets and growing pigs, respectively. In addition, phytase also increased (p < 0.001) P and Ca retention by 6.1 and 9.4% points, respectively, in nursery pigs and ash, P, and Ca contents in metacarpal bones by 17.7, 15.0, and 15.2%, respectively, in growing pigs. The final BW, ADG, G:F ratio, and bone traits in animals fed the NC diet supplemented with phytase were comparable to animals fed the PC diet. This finding indicates the ability of this novel biosynthetic phytase to restore performance and bone mineralization by improving the availability of P and Ca in piglets and growing pigs fed P- and Ca-deficient diets.

Ileal phosphorus digestibility of soybean meal for broiler chickens remains consistent across institutions in a collaborative study regardless of non-phytate phosphorus concentration in the pre-experimental starter diet

The same experimental protocol was used in 4 institutions to evaluate the impact of non-phytate phosphorus (nPP) concentration in the starter diet on regression method-derived ileal P digestibility of soybean meal (SBM) during the subsequent grower phase. A total of 1,536 Ross 308 male broiler chickens on d 0 post hatching were allotted to 2 pre-experimental starter diets that contained 3.5 or 4.5 g nPP/kg (96 replicate cages per diet, 8 birds per cage) for 18 d. Subsequently, 576 birds from each starter diet were selected and allocated to 3 experimental semi-purified grower diets containing 400, 510, or 620 g SBM/kg (32 replicate cages per diet, 6 birds per cage) for 3 d until collection of ileal digesta. Statistical analysis was conducted as a randomized complete block design with the starter period as whole plot and the grower period as split-plot. The only significant 2-way interaction was between grower diet and experimental institution (P < 0.05) on BW gain and gain to feed ratio. The main effect of institution and grower diet impacted (P < 0.05) feed intake, the digestibility of DM, P, and calcium, and disappearance of inositol hexakisphosphate (InsP6) in the grower diets. Birds fed the 3.5 g nPP/kg starter diet had lower (P < 0.05) BW gain and feed intake during the grower period, but presented higher (P < 0.05) digestibility of P and disappearance of InsP6 compared with the birds that were fed the 4.5 g nPP/kg starter diet. Regression method-derived ileal P digestibility of SBM was determined to be 46 or 42% for the respective 3.5 or 4.5 g nPP/kg pre-experimental starter diet and was not affected by the nPP concentration or by the institution. In conclusion, the experimental protocol used in the current study resulted in similar estimates across multiple institutions and is thus endorsed for future application in studies that aim to expand the database of digestible P content in plant source feed ingredients.

Effects of dietary-reduced nitrogen (N) and phosphorus (P) on N and P balance, retention and nutrient digestibility of contemporary fattening pigs fed ad libitum

The reduction of nitrogen (N) and phosphorus (P) in fattening pigs' diets is one possible approach to lower N and P excretion in livestock farming relative to N and P intake. Due to the implementation of the European Nitrates Directive and the consecutive amendments to the German fertiliser legislation since 2017, N- and P-reduced diets for fattening pigs are becoming more and more important and are increasingly used in practice. To investigate the effects of such diets on N and P balance and retention as well as on nutrient digestibility of contemporary fattening pigs, a balance experiment was performed with eight barrows (average live weight = 61.5 ± 2.1 kg) which were surgically fitted with a simple T-cannula at the terminal ileum. The pigs received a control diet meeting nutrient requirements (CON) and an N- and P-reduced diet (NPred) ad libitum (n = 4/diet) in a 3-phased feeding regimen (3 weeks/phase). In the last week of each phase, faeces and urine were collected quantitatively for 5 days followed by a 2 × 12 hours collection of ileal digesta. Daily feed intake, live weight gain and feed-to-gain ratio did not differ between CON and NPred. NPred-fed pigs consumed 10.5% (p = 0.006) and excreted 28.3% (p = 0.028) less N than CON-fed pigs. Phosphorus excretion was lowered by 15.1% in NPred-fed pigs (p = 0.012). N and P retention did not differ between CON and NPred, but were elevated in comparison to other studies. N and P efficiency, expressed as nutrient retention divided by nutrient intake, was higher in NPred - than CON-fed pigs (N: 68 vs 60%, P: 54.2 vs 49.3%). Apparent post-ileal digestibility coefficient (DCpost-ileal) and apparent total tract digestibility coefficient (DCtotal) of crude protein were higher in NPred - than CON-fed pigs (p < 0.013), but apparent precaecal digestibility coefficient (DCpc) of crude protein was unaffected by diet. DCpc, DCpost-ileal and DCtotal of P were similar for CON- and NPred-fed pigs. NPred-fed pigs showed an elevated DCpc and DCtotal of organic matter, N-free-extractives and starch compared to CON-fed pigs. DCpc of calcium was also higher in NPred-fed pigs. In conclusion, the results suggest that N- and P-reduced feeding of fattening pigs remains an effective strategy to lower the N and P release into the environment. Furthermore, results indicate that N- and P-reduced feeding leads to a higher N and P efficiency in contemporary fattening pigs.

Autophagy-mediated ferroptosis involved in nickel-induced nephrotoxicity in the mice

Nickel, as a widely polluted metal, has been shown nephrotoxicity. Ferroptosis is a new type of cell death driven by iron-dependent lipid peroxidation. Our study found that nickel chloride (NiCl₂) induced ferroptosis in mouse kidney and TCMK-1 cells. The iron content was significantly increased in the kidney and TCMK-1 cells after NiCl₂ treatment. Lipid peroxidation and MDA content were significantly increased, and GSH content and T-SOD activity were significantly decreased after exposure to NiCl₂. Moreover, NiCl₂ increased COX-2 protein levels, decreased SLC7A11 and GPX4 protein levels, and elevated Ptgs2 mRNA levels. Next, the mechanism of Ni-induced ferroptosis was investigated. The results showed that NiCl₂ induced autophagy in TCMK-1 cells, which promoted ferroptosis induced by NiCl₂. Furthermore, the data of autophagy activation or inhibition experiment showed that autophagy facilitated ferroptosis through the degradation of the iron regulation protein NCOA4 and FTH1. Otherwise, iron chelator DFOM treatment inhibited ferroptosis induced by NiCl₂. Finally, ferroptosis inhibitor Fer-1 treatment significantly alleviated cytotoxicity induced by NiCl₂. To sum up, our above results showed that ferroptosis is involved in NiCl₂-induced nephrotoxicity, and NiCl₂ induces autophagy-dependent ferritin degradation, releases iron ions, leads to iron overload, and induces ferroptosis. This study supplies a new theoretical foundation for the study of nickel and renal toxicity.

Dietary Supplementation of Lactobacillus johnsonii RS-7 Improved Antioxidant and Immune Function of Weaned Piglets

We investigated the effects of dietary supplementation of lactic acid bacteria on the immune and antioxidant performance of weaned pigs. A total of 128 Duroc × Landrace × Yorkshire piglets weaned on day 28 with an average body weight of 8.95 ± 1.15 kg were selected and randomly divided into four treatment groups according to body weight and sex for a 28-day study. The four dietary treatments were basal diet (CON), and CON with 0.05% (LJ0.05), 0.1% (LJ0.1), and 0.2% (LJ0.2) Lactobacillus johnsonii RS-7, respectively. The lowest feed-to-gain ratio (F:G) was found when LJ0.1 was added to the diet. The addition of compound lactic acid bacteria to the diet increased the concentrations of TP, ALB, IgA, and IgM on day 14 and IgG, IgA, and IgM on day 28 (p < 0.05) in the blood, with trait values greater for pigs fed LJ0.1 than CON pigs (p < 0.05). Concentrations of antioxidants (CAT, T-AOC, MDA, T-SOD, and GSH) in serum, intestinal mucosa, spleen, liver, and pancreas improved. In summary, dietary supplementation of Lactobacillus johnsonii RS-7 improved the antioxidant and immune function of weaned piglets.

Effects of Equol Supplementation on Growth Performance, Redox Status, Intestinal Health and Skeletal Muscle Development of Weanling Piglets with Intrauterine Growth Retardation

Animals with intrauterine growth retardation (IUGR) usually undergo injured postnatal growth and development during the early period after birth. Equol (Eq), an isoflavan produced by gut bacteria in response to daidzein intake, has various health benefits. Therefore, the objective of this study was to evaluate whether Eq supplementation can influence the growth performance, redox status, intestinal health and skeletal muscle development of weanling piglets with IUGR. A total of 10 normal-birth-weight (NBW) newborn female piglets and 20 newborn female piglets with IUGR were selected. After weaning at the age of 21 d, 10 NBW piglets and 10 IUGR piglets were allocated to the NBW group and IUGR group, respectively, and offered a basal diet. The other 10 IUGR piglets were allocated to the IUGR + Eq group and offered a basal diet with 50 mg of Eq per kg of diet. The whole trial lasted for 21 d. At the end of the feeding trial, all piglets were sacrificed for the collection of serum, intestinal tissues and skeletal muscles. Supplementation with Eq increased the average daily gain (ADG), average daily feed intake (ADFI), duodenal villus height to crypt depth ratio (V/C), jejunal villus height and V/C, but reduced the duodenal crypt depth in neonatal piglets with IUGR. Meanwhile, Eq supplementation elevated the activities of superoxide dismutase (SOD) and catalase (CAT) in the serum and duodenum and the activity of SOD in the jejunum, but lowered malondialdehyde (MDA) content in the serum, jejunum and ileum of piglets with IUGR. In addition, supplementation with Eq reduced diamine oxidase (DAO) activity and the levels of D-lactate and endotoxin in serum, and the tumor necrosis factor-α (TNF-α) level in jejunum and ileum, whereas the concentration of serum immunoglobulin G (IgG) and the mRNA levels of intestinal barrier-related markers in jejunum and ileum of IUGR piglets were increased. Furthermore, supplementation with Eq elevated the percentage of fast-fibers and was accompanied with higher mRNA expression of myosin heavy chain IIb (MyHC IIb) and lower mRNA levels in MyHC I in the longissimus thoracis (LT) muscle of IUGR piglets. In summary, Eq supplementation can promote antioxidant capacity, maintain intestinal health and facilitate skeletal muscle development, thus resulting in the higher growth performance of IUGR piglets.

Effects of fermented soybean meal supplementation on the growth performance and apparent total tract digestibility by modulating the gut microbiome of weaned piglets

This study investigates the effects of soybean meal fermented by Enterococcus faecium as a replacement for soybean meal on growth performance, apparent total tract digestibility, blood profile and gut microbiota of weaned pigs. Eighty piglets (weaned at 21 days) [(Landrace × Yorkshire) × Duroc] with average body weight of 6.52 ± 0.59 kg) were selected and assigned to 4 treatments/4 replicate pens (3 barrows and 2 gilts). The four diets (SBM, 3, 6 and 9% FSBM) were formulated using fermented soybean meal to replace 0, 3, 6 and 9% of soybean meal, respectively. The trial lasted for 42 days phase 1, 2 and 3. Result showed that supplemental FSBM increased (P < 0.05) the body weight gain (BWG) of piglets at day 7, 21 and 42 and ADG at days 1-7, 8-21, 22-42 and 1-42, and ADFI at days 8-21, 22-42 and 1-42 and G: F at days 1-7, 8-21 and 1-42, and crude protein, dry matter, and gross energy digestibility at day 42, and lowered (P < 0.05) diarrhea at days 1-21 and 22-42. The concentration of glucose levels, WBC, RBC, and lymphocytes were increased while, concentration of BUN level in the serum was lowered in the FSBM treatment compared to the SBM group (P < 0.05). Microbiota sequencing found that FSBM supplementation increased the microbial Shannon, Simpsons and Chao indexs, (P < 0.05) and the abundances of the phylum Firmicutes, and genera prevotella, Lactobacillus, Lachnospiraceae and Lachnoclostridium (P < 0.05), lower in the abundances of the phylum bacteroidetes, Proteobacteria, genera Escherichia-Shigella, Clostridium sensu stricto1, Bacteroides and Parabacteroides (P < 0.05). Overall, FSBM replacing SBM improved the growth performance, apparent total tract digestibility, and blood profiles; perhaps via altering the faecal microbiota and its metabolites in weaned pigs. The present study provides theoretical support for applying FSBM at 6-9% to promote immune characteristics and regulate intestinal health in weaning piglets.

The Effects of Phytase and Non-Starch Polysaccharide-Hydrolyzing Enzymes on Trace Element Deposition, Intestinal Morphology, and Cecal Microbiota of Growing-Finishing Pigs

This study investigated the effects of supplementing phytase and non-starch polysaccharide-degrading enzymes (NSPases) to corn-soybean meal-based diet on the growth performance, trace element deposition, and intestinal health of growing-finishing pigs. Fifty pigs were randomly assigned into the control (basal diet), phytase (basal diet + 100 g/t of phytase), β-mannanase (basal diet + 40 g/t of β-mannanase), β-glucanase (basal diet + 100 g/t of β-glucanase), and xylanase (basal diet + 100 g/t of xylanase) groups. The results show that the supplementation of phytase and NSPases had no impacts (p  >  0.05) on the growth performance of pigs. Compared with the control group, pigs fed with xylanase had higher (p < 0.05) Zn concentrations in the ileum and muscle and those fed with phytase had higher (p < 0.05) Zn concentrations in the ileum. Phytase and xylanase supplementation decreased (p < 0.05) fecal Zn concentrations in pigs compared with the control group (p < 0.05). In addition, phytase, β-mannanase, β-glucanase, and xylanase supplementation up-regulated (p < 0.05) the FPN1 expression, whereas xylanase up-regulated (p < 0.05) the Znt1 expression in the duodenum of pigs compared with the control group. Moreover, phytase, β-glucanase, and xylanase supplementation up-regulated (p < 0.05) the jejunal Znt1 expression compared with the control group. The intestinal morphology results show that the phytase, β-mannanase, and xylanase groups had increased villus heights (VHs), an increased villus height-crypt depth ratio (VH:CD), and decreased crypt depths (CDs) in the duodenum, whereas phytase, β-mannanase, β-glucanase, and xylanase groups had decreased VH and VH:CD, and increased CD in the jejunum compared with the control group (p < 0.05). Pigs fed with exogenous enzymes had decreased bacterial diversity in the cecum. The dietary supplementation of NSPases increased the relative abundance of Firmicutes and decreased spirochaetes (p < 0.05). Compared with the control group, dietary NSPase treatment decreased (p < 0.05) the opportunistic pathogens, such as Treponema_2 and Eubacterium_ruminantium. Moreover, the relative abundances of Lachnospiraceae_XPB1014 and Lachnospiraceae were enriched in the β-glucanase and β-mannanase groups (p < 0.05), respectively. In conclusion, phytase and xylanase supplementation may promote zinc deposition in pigs. Additionally, the supplementation of NSPases may improve the gut health of pigs by modulating the intestinal morphology and microbiota.

- Invited Review - Mineral composition and phosphorus digestibility in feed phosphates fed to pigs and poultry

Phosphorus (P) is a macro mineral needed for bone mineralization and cell membrane structure and P is also involved in several fundamental pathways of metabolism in the body. Because of the low concentration and digestibility of P in plant ingredients that are the main components of diets for poultry and pigs, feed phosphates are usually included in diets in addition to the P contributed by plant ingredients. The most widely used feed phosphates in poultry and swine diets are dicalcium phosphate (DCP) and monocalcium phosphate (MCP), but tricalcium phosphate (TCP), monosodium phosphate (MSP), and magnesium phosphate (MgP) may be used as well. Because feed phosphates are mostly produced from rock phosphate, feed phosphates have impurities that contain minerals other than P. Concentrations of P in feed phosphates range from 14.8% (MgP) to 25.7% (MSP). The standardized total tract digestibility (STTD) of P in pigs ranges from 71% (TCP) to 95% (MSP). The STTD of Ca and the standardized ileal digestibility (SID) of P and Ca in feed phosphates fed to pigs and poultry have been determined only in a few experiments. Available data indicate that the STTD of Ca and SID of P in MCP are greater than in DCP in both poultry and pigs, but the SID of Ca is similar between DCP and MCP fed to broilers. Information on mineral concentrations and digestibility values in feed phosphates is needed in diet formulation for pigs and poultry, but if diets are formulated to contain equal concentrations of digestible P and Ca, it is unlikely that animal performance will be impacted by the source of feed phosphates used in the diet.

Dietary Complex Probiotic Supplementation Changed the Composition of Intestinal Short-Chain Fatty Acids and Improved the Average Daily Gain of Growing Pigs

At present, probiotics are being extensively evaluated for their efficacy as an alternative to antibiotics, and their safety in livestock production. In this study, 128 (Duroc, Yorkshire and Landrace) pigs with an average initial body weight of 28.38 ± 0.25 kg were allocated to four dietary treatments in a randomized complete-block design. There were eight pens per treatment, with four pigs per pen (two barrows and two gilts). Dietary treatments included: (1) control diet; (2) control diet + 0.05% complex probiotic; (3) control diet + 0.1% complex probiotic; (4) control diet + 0.2% complex probiotic. During the 28-day experimental period, the feeding of 0.1% complex probiotic in the diet increased body weight and average daily gain (p < 0.05). The addition of complex probiotics decreased total cholesterol and glucose concentrations in the blood (p < 0.01). Acetate concentrations in the blood increased from 0.1% complex probiotic in the diet (p < 0.05), while NH₃ and H₂S emissions in the feces decreased (p < 0.05) from 0.1% or 0.2% complex probiotic in the diet. In conclusion, dietary complex probiotic supplementation changed the composition of intestinal short-chain fatty acids and improved growth performance for growing pigs.

Bacillus subtilis and Pichia farinose mixture improves growth performance and nutrient absorption capacity in broiler chicks

Introduction

This study evaluated the effects of dietary supplementation of Bacillus subtilis and Pichia farinose mixture (BPM) on growth performance, apparent ileal digestibility, cecal bacteria counts, small intestinal morphology and digestive enzymes activities, and jejunal nutrient transporters gene expression in broiler chicks.

Methods

A total of 768 one-day-old Ross 308 broiler chicks were randomly Q18 assigned into 3 groups based on the initial body weight (42.00 ± 0.08 g). The experimental periods were 35 days. There were 16 replicates per group and 16 birds per cage. Dietary treatments included a basal diet supplemented with 0, 0.1, or 0.2% BPM to form CON, BPM0.1 (consisting Bacillus subtilis with 1.0 × 107 viable spore and Pichia farinose with 1.0 × 107 viable spore per kg diet), and BPM0.2 (consisting Bacillus subtilis with 2.0 × 107 viable spore and Pichia farinose with 2.0 × 107 viable spore per kg diet) groups.

Results and discussion

Dietary supplementation of graded levels of BPM has positive effects on growth performance of broiler chicks, manifesting in the increase of body weight gain during days 1-35 as well as the decrease of feed conversion ratio during days 1-7, 21-35, and 1-35. Moreover, BPM supplementation positively improved ileal energy and crude protein digestibility, increased Lactobacillus counts, optimized intestinal morphology, enhanced intestinal digestive enzymes activities, and upregulated jejunal SGLT-1, GLUT-2, and PEPT-1 expression. Therefore, BPM supplementation improved growth performance of broiler chicks, which was partially related to the improvement in intestinal nutrient absorption capacity.

Effects of 25(OH)VD3 on Growth Performance, Pork Quality and Calcium Deposit in Growing-Finishing Pigs

The study was conducted to evaluate the effects of 25(OH)VD3 with different inclusion levels of 0, 25, 50 and 75 μg/kg in the diet on growth performance, nutrient digestibility, bone properties and pork quality in growing-finishing pigs. The results showed that the average daily gain (p < 0.05) and body weight (p < 0.10) of pigs showed a trend of increasing quadratically as inclusion levels of 25(OH)VD3 increased. Dietary supplementation of 50 μg/kg 25(OH)VD3 increased calcium digestibility compared with the 0 μg/kg group (p < 0.05), and calcium and phosphorus digestibility increased quadratically as inclusion levels of 25(OH)VD3 increased (p < 0.05). Dietary supplementation of 50 μg/kg 25(OH)VD3 increased concentrations of polyunsaturated fatty acids, and decreased contents of saturated and monounsaturated fatty acids in the longissimus dorsi of pigs (p < 0.05). The addition of 25, 50 and 75 μg/kg 25(OH)VD3 to the diet increased breaking strength and bone stiffness in the tibia compared with the 0 μg/kg group (p < 0.05). Dietary supplementation of 50 μg/kg 25(OH)VD3 improved the activities of superoxide dismutase (SOD) and catalase (CAT), and increased the messenger RNA (mRNA) expression of Cu/Zn SOD in the longissimus dorsi compared with the 0 μg/kg group (p < 0.05). Supplementing 50 μg/kg 25(OH)VD3 improved the mRNA expression of calcium-binding protein D9k (CaBP-D9k) and D28k (CaBP-D28K) in the liver compared with the 0 μg/kg 25(OH)D3 group (p < 0.05). In conclusion, a diet with an added dose of 50 μg/kg 25(OH)VD3 showed a greatest growth performance of growing-finishing pigs, and 25(OH)VD3 enhanced calcium deposition and antioxidant capacity in the longissimus dorsi, which may be associated with improved expression of calcium ion channel proteins.

Reduced Meal Frequency Decreases Fat Deposition and Improves Feed Efficiency of Growing-Finishing Pigs

An experiment was conducted to examine the effect of meal frequency on growth performance, nutrient digestibility, carcass quality, and lipid metabolism in growing−finishing pigs. Sixty-four Duroc × Landrace × Yorkshire barrows and gilts (26.40 ± 2.10 kg initial body weight) were used in a 112-d experiment in a randomized complete blocked design. The two treatments were the free-access feed group (FA) and the three meals per day group (M3), respectively. The result showed that the average daily feed intake (ADFI) and F: G of the FA group were significantly higher than that in the M3 group during the whole experiment (p < 0.05). Reducing meal frequency also decreased the concentration of triglycerides and urea nitrogen but increased the concentration of insulin and free fatty acids in the blood (p < 0.05). Reducing meal frequency decreased compositions of backfat, belly, and fatty pieces but increased compositions of ham, longissimus muscle, and lean pieces in the carcass (p < 0.05). Greater enzyme activities of ME and FAS and higher mRNA expression of FAS and PPARγ were found in the LM of FA pigs compared with M3 pigs (p < 0.05). In summary, a lower meal frequency improves feed efficiency by regulating lipid metabolism and reducing fat deposition.

Phytase Supplementation of Four Non-Conventional Ingredients Instead of Corn Enhances Phosphorus Utilization in Yellow-Feathered Broilers

The present study was conducted to evaluate the effects of unconventional feedstuff such as wheat, broken rice, distillers dried grains with soluble (DDGS), and wheat bran, replacing 15% of the corn in the basal diet and the supplementation of bacterial phytase on nutrition digestibility. A total of 500 yellow-feathered broilers with similar body weights of 1.65 ± 0.15 kg were divided into 10 dietary treatments with 5 replicates per treatment (5 male and 5 females per cage). The AME and AIDE were significantly higher when supplied with phytase (p < 0.01) in the DDGS group. The ileal and total tract digestibility of calcium and phosphorus were significantly increased in the phytase-supplied group (p < 0.001). Additionally, the ileal digestibility of CP was increased when phytase was supplemented (p < 0.001). The results infer that the wheat, broken rice, DDGS, and wheat bran had no negative effect when replacing 15% corn. Supplementing 0.02% phytase in their diets can effectively optimize nutrient digestibility in yellow broilers.