Effect of particle size of wheat on nutrient digestibility, growth performance, and gut microbiota in growing pigs

Nutritional guide to feeding wheat and wheat co-products to swine: a review

Inclusion of wheat grain can offer feeding opportunities in swine diets because of its high starch, crude protein (CP), amino acid (AA), and phosphorus (P) content. High concentrations of starch within wheat grain makes it a good energy source for swine. Mean energy content of wheat was 4,900 and 3,785 kcal/kg dry matter (DM) for digestible energy and metabolizable energy, respectively. CP concentration can vary based on the class of wheat which include hard red winter, hard red spring, soft red winter, hard white, soft white, and durum. The average CP of all wheat data collected in this review was 12.6% with a range of 8.5% to 17.6%. The AA concentration of wheat increases with increasing CP with the mean Lys content of 0.38% with a standardized ileal digestibility (SID) of 76.8%. As CP of wheat increases, the SID of AA in wheat also increases. Mean P of wheat was 0.27% and median P was 0.30%. Off-quality wheat is often associated with sprouts, low-test weight, or mycotoxin-contamination. Sprouted and low-test weight wheat are physical abnormalities associated with decreased starch within wheat kernel that leads to reductions in energy. The assumed energy value of wheat grain may need to be reduced by up to 10% when the proportion of sprouted to non-sprouted wheat is up to 40% whereas above 40%, wheat's energy may need to be reduced by 15% to 20%. Low-test weight wheat appears to not influence pig performance unless it falls below 644 kg/m3 and then energy value should be decreased by 5% compared to normal wheat. Deoxynivalenol (DON) contamination is most common with wheat grain. When content is above the guidance level of 1 mg/kg of DON in the complete diet, each 1 mg/kg increase in a DON-contaminated wheat-based diet will result in a 11% and 6% reduction in ADG and ADFI for nursery pigs, and a 2.7% and 2.6% reduction in ADG and ADFI, in finishing pigs, respectively. Wheat co-products are produced from the flour milling industry. Wheat co-products include wheat bran middlings, millrun, shorts, and red dog. Wheat co-products can be used in swine diets, but application may change because of differences in the final diet energy concentration due to changes in the starch and fiber levels of each wheat co-product. However, feeding wheat co-products are being evaluated to improve digestive health. Overall, wheat and wheat co-products can be fed in all stages of production if energy and other nutrient characteristics are considered.

Biomass attachment and microbiota shifts during porcine faecal in vitro fermentation of almond and macadamia nuts differing in particle sizes

Nuts are highly nutritious and good sources of dietary fibre, when consumed as part of a healthy human diet. Upon consumption, nut particles of various sizes containing lipids entrapped by the plant cell walls enter the large intestine where they are fermented by the resident microbiota. This study investigated the microbial community shifts during in vitro fermentation of almond and macadamia substrates, of two particle sizes including fine particles (F = 250-500 μm) and cell clusters (CC = 710-1000 μm). The aim was to determine how particle size and biomass attachment altered the microbiota. Over the 48 h fermentation duration, short chain fatty acid concentrations increased due to particle size rather than nut type (almond or macadamia). However, nut type did change microbial population dynamics by stimulating specific genera. Tyzzerella, p253418B5 gut group, Lachnospiraceae UCG001, Geotrichum, Enterococcus, Amnipila and Acetitomaculum genera were unique for almonds. For macadamia, three unique genera including Prevotellaceae UCG004, Candidatus Methanomethylophilus and Alistipes were noted. Distinct shifts in the attached microbial biomass were noted due to nut particle size. Bacterial attachment to nut particles was visualised in situ during fermentation, revealing a decrease in lipids and an increase in attached bacteria over time. This interaction may be a pre-requisite for lipid breakdown during nut particle disappearance. Overall, this study provides insights into how nut fermentation alters the gut microbiota and the possible role that gut microbes have in lipid degradation.

Effects of different processing techniques of palm kernel cake on processing quality of pellet feed, nutrient digestibility, and intestinal microbiota of pigs

The present study was conducted to investigate the effects of extrusion, fermentation, and enzymolysis of palm kernel cake on processing quality of pellet feed, nutrient digestibility, and intestinal microbiota of pigs. First, the pretreatment parameters of extrusion, enzymolysis, and fermentation of palm kernel cake were optimized. Then, PKC after three processing techniques were used to prepare pellet feed. A total of 160 crossbred piglets (Duroc × Landrace × Yorkshire) with an average body weight of 28 ± 0.5 kg were used in an 8-wk feeding experiment. Pigs were randomly assigned to five treatments with four replicates per treatment and eight pigs per replicates. The five experimental groups were as follows: basal diet group (whole corn-soybean meal), 10% PKC group (PKC), 10% extrusion PKC group (PPKC), 10% enzymolysis PKC group (EPKC), and 10% fermented PKC group (FPKC), respectively. At the end of the experiment, four pigs from each treatment (randomly collected one pig per pen) were sacrificed by administering a pentobarbital overdose, the gut and blood samples were collected for the quantification analysis of microbiota, hematological parameters, and apparent total tract nutrient digestibility. The results showed that all three processing techniques significantly decreased the contents of crude fiber of PKC (P < 0.01), pulverization rate (P < 0.01), powder content (P < 0.01), and increased the hardness and gelatinization starch of pellet feed (P < 0.05) compared to PKC group. In addition, PPKC significantly improved the dry matter, crude protein, and ether extract content, blood indices and average daily feed intake compared to PKC group (P < 0.01), while the parameters were similar among FPKC, EPKC, and control group (P > 0.01). Furthermore, all three processing techniques significantly increased the Lactobacillus and decreased the Escherichia levels in feces or gut compared to PKC. Collectively, extrusion, fermentation, and enzymolysis of PKC had positively enhanced the pellet quality, growth performance, nutrient digestibility, and gut microbiota, extrusion exhibited a superior feeding effect compared to fermentation and enzymolysis.

Effects of corn particle size on energy and nutrient digestibility in diets fed to young pigs and adult sows

Objective

This research was carried out to investigate the effects of corn particle size on the apparent total tract digestibility (ATTD) of energy and nutrients fed to pigs at four different growth stages and therefore to provide basis for better application of corn in pig feeds.

Methods

Eighteen weanling piglets, 18 growing barrows, 24 gestating sows and 24 lactating sows were used in this study. Within each stage, pigs were allotted to 1 of 3 or 4 corn-soybean meal diets which were formulated with different corn particle size in a completely randomized design with 6 replicate pigs per diet. Each stage lasted for 19 days, including 7 days for cages adaptation, 7 days for adaptation to diets and followed by 5 days for total collection of feces and urine.

Results

For nursery and growing stages, the results showed that digestible energy content and ATTD of gross energy (GE), dry matter (DM), neutral detergent fiber (NDF), and acid detergent fiber (ADF) was increased (p<0.05) as the corn particle size reduced. Meanwhile, the metabolizable energy content and ATTD of crude protein (CP) tended to increase. For gestating sows, no differences were found in the ATTD of nutrients among dietary treatments. As for lactating sows, there were linear and quadratic increases (p<0.05) in the ATTD of DM, GE, NDF as the corn being finer milled. Quadratic response in ATTD of ADF and CP (p<0.05) were observed as sows fed with four different diets.

Conclusion

Reducing corn particle size can increase digestibility of nutrients fed to young pigs and lactating sows. No effects were observed in present experiment when gestating sows were fed with different particle sized corn.

Effect of Corn Particle Size on the Particle Size of Intestinal Digesta or Feces and Nutrient Digestibility of Corn–Soybean Meal Diets for Growing Pigs

This study was conducted to evaluate the effect of corn particle size on the particle size of intestinal digesta or feces and nutrient digestibility of corn–soybean meal diets. Twenty-four growing barrows (initial BW: 21.9 ± 1.62 kg) were randomly divided into 4 groups of 6 pigs. A T-cannula was surgically placed in the anterior duodenum (about 50 cm from pylorus) of pigs in Groups 1 and 2 or in the distal ileum of pigs in Groups 3 and 4. Corn used to formulate diets had mean particle size (MPS) of 365 µm (Corn 1) or 682 µm (Corn 2), resulting in diets with MPS of 390 µm (Diet 1) or 511 μm (Diet 2). Diet 1 or 2 were randomly assigned within pig Groups 1 or 2 and 3 or 4. The digestive enzyme activities of duodenal fluid, particle size of intestinal digesta and feces, as well as nutrient digestibility, were determined for each pig as the experiment unit. The MPS of duodenal digesta (181 vs. 287 µm, p < 0.01), ileal digesta (253 vs. 331 µm, p < 0.01), and feces (195 vs. 293 µm, p < 0.01) was significantly reduced for pigs fed Diet 1 vs. Diet 2, respectively. Compared with Diet 2, Diet 1 significantly reduced the proportion of particles above 0.5 mm, but significantly increased the proportion of particles between 0.072 and 0.5 mm (p < 0.01) in digesta and feces (p < 0.01). Diet 1 significantly increased solubles percentage (<0.072 mm) in duodenal digesta (p < 0.05) but did not affect solubles percentage in ileal digesta and feces. The MPS of diet did not affect the activities of amylase, trypsin, and chymotrypsin in the duodenal fluid and the apparent total tract digestibility (ATTD) of dry matter, gross energy, crude protein, ether extract, neutral detergent fiber (NDF) and acid detergent fiber (ADF) in pigs offered Diet 1 compared to Diet 2. The in vitro digestible energy (IVDE) (3706 vs. 3641 kcal/kg; p = 0.03) was greater for Corn 1 vs. Corn 2. However, no significant difference was observed in IVDE (3574 vs. 3561 kcal/kg; p = 0.47) for Diet 1 vs. Diet 2. In conclusion, the particle size of digesta and feces was dependent on the dietary particle size. However, the digestive enzyme activities of duodenal fluid and ATTD of energy and nutrients were not affected by reducing dietary MPS from 511 to 390 µm.

Effects of grinding method and particle size of wheat grain on energy and nutrient digestibility in growing and finishing pigs

Feed grains are processed to improve their value in pig diets by exposing kernel contents to enzymatic and microbial action. The objective of this study was to quantify the effect of reducing mean particle size (PS) of wheat grain ground with two different grinding methods (GMs) on the apparent total tract digestibility (ATTD) of nutrients and energy in growing and finishing pigs. Forty-eight barrows were housed in individual pens for 11 d for two periods. Pigs were randomly assigned to a 3 × 2 × 2 factorial experimental design: three target mean PS of wheat grain (300, 500, and 700 µm), two GMs (roller mill and hammermill), and two body weight (BW) periods (growing period; initial BW of 54.9 ± 0.6 kg and finishing period; initial BW of 110.7 ± 1.4 kg). Diets contained one of six hard red wheat grain samples, vitamins, minerals, and titanium dioxide as an indigestible marker. Feed allowance provided 2.5 (for the two lightest pigs in each treatment) or 2.7 (for the remaining six pigs in each treatment) times the estimated daily maintenance energy requirement for each growth stage. Fecal samples were collected for the last 3 d of each period. Data were analyzed as a linear mixed model with pig as a random effect and PS, GM, and BW period and their interactions as fixed effects utilizing the MIXED procedure of SAS. Growing pigs had greater (P < 0.05) ATTD of dry matter (DM), gross energy (GE), N, acid hydrolyzed ether extract (AEE), and neutral detergent fiber (NDF) by lowering mean PS from 700 to 500 μm using either a roller mill or a hammermill. However, digestibility did not increase when PS was reduced from 500 to 300 μm, except for AEE (P < 0.05). Finishing pigs had greater ATTD of DM, GE, N, AEE, and NDF by lowering mean PS with a hammermill from 700 to 500 μm (P < 0.05), but it was greater for 500 μm than for 300 μm (P < 0.05). Using a roller mill reduced the ATTD of DM and NDF by lowering PS from 700 to 300 μm (P < 0.05). The ATTD of GE decreased by lowering PS from 700 to 500 μm with a roller mill (P < 0.05) for finishing pigs. The ATTD of N and AEE for finishing pigs were similar from 700 to 300 μm when ground by a roller mill. These data suggest that the PS that maximized digestibility for a hammermill is 500 μm for both growing and finishing pigs. However, for the roller mill, the PS resulting in the best digestibility were 500 and 700 μm for growing and finishing pigs, respectively.

Effects of particle size of ground alfalfa hay on caecal bacteria and archaea populations of rabbits

This work was aimed to investigate the effects of the different particle size of ground alfalfa hay on caecal microbial and archeal communities of rabbits. One hundred-twenty New Zealand rabbits (950.3 ± 8.82 g) were allocated into four treatments, with five replicates in each treatment and six rabbits in each replicate. The particle sizes of the alfalfa meal in the four treatment diets were 2,500, 1,000, 100 and 10 µm respectively, while the other ingredients were ground through a 2.5 mm sieve. High-throughput sequencing technology was applied to examine the differences in bacteria and methanogenic archaea diversity in the caecum of the four treatment groups of rabbits. A total of 745,946 bacterial sequences (a mean of 31,081 ± 13,901 sequences per sample) and 539,227 archaeal sequences (a mean of 22,468 ± 2,443 sequences per sample) were recovered from twenty-four caecal samples, and were clustered into 9,953 and 2,246 OTUs respectively. A total of 26 bacterial phyla with 465 genera and three archaeal phyla with 10 genera were identified after taxonomic summarization. Bioinformatic analyses illustrated that Firmicutes (58.69% ∼ 68.50%) and Bacteroidetes (23.96% ∼ 36.05%) were the two most predominant bacterial phyla and Euryarchaeota (over 99.9%) was the most predominant archaeal phyla in the caecum of all rabbits. At genus level, as the particle size of alfalfa decreased from 2,500 to 10 µm, the relative abundances of Ruminococcaceae UCG-014 (P < 0.001) and Lactobacillus (P = 0.043) were increased and Ruminococcaceae UCG-005 (P = 0.012) was increased first and then decreased when the alfalfa particle size decreased, while Lachnospiraceae NK4A136 group (P = 0.016), Ruminococcaceae NK4A214 (P = 0.044), Christensenellaceae R-7 group (P = 0.019), Lachnospiraceae other (Family) (P = 0.011) and Ruminococcaceae UCG-013 (P = 0.021) were decreased. The relative abundance of Methanobrevibacter was increased from 62.48% to 90.40% (P < 0.001), whereas the relative abundance of Methanosphaera was reduced from 35.47% to 8.62% (P < 0.001). In conclusion, as the particle size of alfalfa meal decreased, both the bacterial and archaeal population in the caecum of rabbit experienced alterations, however archaea response earlier than bacteria to the decrease of alfalfa meal particle size.

Effects of particle size and lipid form of corn on energy and nutrient digestibility in diets for growing pigs

Objective

Two experiments were conducted to evaluate the effects of corn particle size and lipid form on the apparent total tract digestibility (ATTD) of energy and nutrients in diets for growing pigs.

Methods

In Exp. 1, thirty barrows (initial body weight [BW], 53.1±3.9 kg) were allotted to 1 of 5 diets formulated with 96.9% corn ground to 441, 543, 618, 659, and 768 μm, respectively. In Exp. 2, thirty-six barrows (initial BW, 54.7±3.6 kg) were allotted to 1 of 6 diets formulated by including 2% or 15% corn germ (CG 2 or CG 15), 1% or 6% corn oil (CO 1 or CO 6), 1% CO+2% corn germ meal (CO 1+CGM 2), or 6% CO+15% corn germ meal (CO 6+CGM 15), respectively.

Results

The ATTD of gross energy (GE) and the digestible energy (DE) in diet and corn grain linearly decreased as the corn particle size increased (p<0.05) from 441 to 768 μm. Particle size had a quadratic effect (p<0.05) on the ATTD of neutral detergent fiber and acid detergent fiber in diets, and which firstly increased and then decreased as the corn particle size increased from 441 to 618 μm and 618 to 768 μm, respectively. The ATTD of GE, ether extract (EE), and the DE in CO 1 diet and CO 6 diet was greater (p<0.05) than that in CG 2 diet and CG 15 diet, respectively. The ATTD of EE in CO 6 diet and CO 6+CGM 15 diet was greater (p<0.05) than that in CO 1 diet and CO 1+CGM 2 diet.

Conclusion

Less than 618 μm was recommended for corn particle size in growing pig’s diet and extracted lipid had greater digestibility than the intact lipid in corn. Higher concentration of extracted CO had greater digestibility of EE compared with lower concentrations of CO diet.

Utilisation of a mix of powdered oils as fat supplement in nursery- and growing-pig diets

Two experiments were conducted to challenge nursery and growing pigs to increased levels of dietary fat (5–10% as fed), using a crystallised powdered oil mix (CPOM), produced by a modified freeze-drying process. Growth performance of nursery pigs was determined and a digestibility trial was also conducted with growing pigs (Experiment 2). The CPOM was compared, at similar levels of lipid inclusion (10% total lipids), with other fat sources commonly used in swine diet, namely soybean oil (SBO) and hydrogenated palm oil. For the growth assay (Experiment 1), the CPOM was prepared and added at different levels (0%, 2.6% and 3.8%) commonly used in commercial diets (Phase 1–4 diets). Seventy-five weaning pigs (28 days of age) were housed in 15 pens (5 pigs per pen) and randomly assigned into the three dietary treatments until 70 days of age. Growth performance and feed utilisation were compared weekly among experimental groups. The use of CPOM improved average daily gain (~60%), and increased average daily feed intake by 40% and 50% at the 2.6% and 3.8% CPOM levels respectively. In the digestibility trial (Experiment 2), pigs fed with 5% incorporation of CPOM (10% of total lipid content) had digestibility of energy and ether extract similar to those fed the SBO-supplemented diet, although the SBO diet had a significantly greater polyunsaturated fatty acid concentration. The powdered crystallisation process of the CPOM fat allowed an equivalent digestibility of this fat source with more saturated fatty acids, and the physical-property effect of this processed oil source on apparent total-tract digestibility should be further studied.