Sorghum as a dietary substitute for corn reduces the activities of digestive enzymes and antioxidant enzymes in pigs

The Antinutritional Factors and Technological Processing of Sorghum and Its Application in Pig Production

Sorghum ranks as the fifth largest grain crop globally, and it has similar levels of crude protein and leucine compared to corn, making it a viable substitute for full or partial corn in pig diets. Sorghum is produced around the world like corn, which is the energy source in pig diets. However, sorghum contains antinutritional factors that adversely affect nutrient absorption, energy, and amino acid availability. Additionally, the low content of essential amino acids, such as lysine (Lys) and methionine (Met), limits its feeding value. Consequently, this paper primarily discusses the antinutritional factors present in sorghum and elaborates on methods to enhance the nutritional value of forage sorghum through processes such as crushing, extrusion, and enzymatic hydrolysis. The nutritional value of sorghum could be improved by adding protease, by extrusion, and by reducing the grain size. Furthermore, this paper summarizes the application of sorghum in pig production to enhance the understanding of forage sorghum among feed enterprises and to provide a theoretical reference for the rational formulation of pig diets.

Effects of multienzyme supplementation on energy and nutrient digestibility in various feed ingredients for pregnant gilts

The utilization of exogenous fiber-degrading enzymes in commercial swine diets is a strategy to increase the nutrient and energy density of poorly digestible ingredients. In a prior set of studies, dietary multienzyme blend (MEblend) supplementation increased the apparent total tract digestibility (ATTD) of nutrients, non-starch polysaccharides, and energy in complete high-fibrous gestation diets by 6% when fed to gestating sows. The current study aimed to determine the effects of MEblend (containing xylanase, β-glucanase, cellulase, amylase, protease, pectinase, and invertase activities) supplementation on ATTD of energy and nutrients of individual feedstuffs commonly used in gestating sow diets across major pork-producing regions worldwide, which differ in their fibrous components. Twenty-seven gilts (initial body weight 176 ± 6.6 kg), in a crossover design with 4 periods (periods 1, 2, 3, and 4 from days 41 to 55, 56 to 70, 71 to 85, and 86 to 100 of gestation, respectively), were allocated to one of 7 diets (with or without MEblend supplementation at 0.1% inclusion; 7 to 8 observations per treatment) to determine the ATTD of energy and neutral detergent fiber. Three diets contained corn, wheat, and sorghum as the sole source of energy. In the other diets, soybean meal (SBM), field peas (FP), canola meal (CM), and sugar beet pulp (SBP) each replaced 25% of the corn in the corn diet to determine the energy value of individual feedstuffs. Data were analyzed using a Student's t-test to evaluate the effect of enzyme supplementation on these feedstuffs. The MEblend increased the metabolizable and net energy of corn (P = 0.10) and wheat (P < 0.01) by 2% and 3%, respectively. The energy content of sorghum was not impacted by MEblend. Furthermore, a 6%, 4%, and 25% increase was observed in metabolizable and net energy of SBM, FP, and CM, respectively (P ≤ 0.05). The energy value in SBP was not affected by MEblend supplementation. In conclusion, supplementing diets with a multienzyme blend increased the energy content of corn, wheat, soybean meal, FP, and CM fed to gestating sows by approximately 2% to 25%, depending on the feedstuffs. The energy value of sorghum and SBP was not affected by the multienzyme blend. This should be considered when formulating fibrous diets for gestating sows to increase nutrient utilization of feedstuffs.

Dietary supplementation of proteases on growth performance, nutrient digestibility, blood characteristics and gut microbiota of growing pigs fed sorghum-based diets

Low-tannin sorghum is an excellent energy source in pig diets. However, sorghum contains several anti-nutritional factors that may have negative effects on nutrient digestibility. The impacts of proteases on growth performance, nutrient digestibility, blood parameters, and gut microbiota of growing pigs fed sorghum-based diets were studied in this study. Ninety-six pigs (20.66 ± 0.65 kg BW) were allocated into three groups (eight pens/group, four pigs/pen): (1) CON (control diet, sorghum-based diet included 66.98% sorghum), (2) PRO1 (CON + 200 mg/kg proteases), (3) PRO2 (CON + 400 mg/kg proteases) for 28 d. No differences were observed in growth performance and apparent total tract digestibility (ATTD) of nutrients between CON and PRO1 groups. Pigs fed PRO2 diet had increased (P < 0.05) BW on d 21 and 28, and increased (P < 0.05) average daily gain during d 14-21 and the overall period compared with pigs fed CON diet. In addition, pigs fed PRO2 diet had improved (P < 0.05) ATTD of gross energy, CP, and DM compared with pigs fed CON and PRO1 diets. Pigs fed PRO2 diet had lower (P < 0.05) plasma globulin (GLB) level and higher (P < 0.05) plasma glucose, albumin (ALB) and immunoglobulin G levels, and ALB/GLB ratio than pigs fed CON and PRO1 diets. Furthermore, pigs fed PRO2 diet had decreased (P < 0.05) the relative abundance of Acidobacteriota at the phylum level and increased (P < 0.05) the relative abundance of Prevotella_9 at the genus level. The linear discriminant analysis effect size analysis also showed that pigs fed PRO2 diet had significantly enriched short-chain fatty acid-producing bacteria, such as Subdoligranulum and Parabacteroides. In conclusion, protease supplementation at 400 mg/kg improved the growth performance of growing pigs fed sorghum-based diets, which may be attributed to the improvement of nutrient digestibility, host metabolism, immune status and associated with the altered gut microbiota profiles.

Adult Ossabaw Pigs Prefer Fermented Sorghum Tea over Isocaloric Sweetened Water

Ossabaw pigs (n = 11; 5-gilts, 6-barrows; age 15.6 ± 0.62 SD months) were exposed to a three-choice preference maze to evaluate preference for fermented sorghum teas (FSTs). After conditioning, pigs were exposed, in four sessions, to choices of white FST, sumac FST, and roasted sumac-FST. Then, pigs were exposed, in three sessions, to choices of deionized H2O (-control; avoidance), isocaloric control (+control; deionized H2O and sucrose), and blended FST (3Tea) (equal portions: white, sumac, and roasted sumac). When tea type was evaluated, no clear preference behaviors for tea type were observed (p > 0.10). When the 3Tea and controls were evaluated, pigs consumed minimal control (p < 0.01;18.0 ± 2.21% SEM), and they consumed great but similar volumes of +control and 3Tea (96.6 and 99.0 ± 2.21% SEM, respectively). Likewise, head-in-bowl duration was the least for -control, but 3Tea was the greatest (p < 0.01; 5.6 and 31.9 ± 1.87% SEM, respectively). Head-in-bowl duration for +control was less than 3Tea (p < 0.01; 27.6 vs. 31.9 ± 1.87% SEM). Exploration duration was the greatest in the area with the -control (p < 0.01; 7.1 ± 1.45% SEM), but 3Tea and +control exploration were not different from each other (1.4 and 3.0 ± 1.45% SEM, respectively). Regardless of tea type, adult pigs show preference for FST, even over +control. Adult pigs likely prefer the complexity of flavors, rather than the sweetness alone.

Sorghum tannin extract impedes in vitro digestibility and fermentability of nutrients in the simulated porcine gastrointestinal tract

The site and extent of digestion of sorghum nutrients affected by tannins in the intestine are not clarified. Porcine small intestine digestion and large intestine fermentation were simulated in vitro to determine the effects of sorghum tannin extract on the digestion and fermentation characteristics of nutrients in the mimicked porcine gastrointestinal tract. In experiment 1, low-tannin sorghum grain without or with 30 mg/g sorghum tannin extract were digested by porcine pepsin and pancreatin to measure in vitro digestibility of nutrients. In experiment 2, the lyophilized porcine ileal digesta from 3 barrows (Duroc × Landrace × Yorkshire, 27.75 ± 1.46 kg) fed the low-tannin sorghum grain without or with 30 mg/g sorghum tannin extract and the undigested residues from experiment 1 were, individually, incubated with fresh pig cecal digesta as inoculums for 48 h to simulate the porcine hindgut fermentation. The results revealed that sorghum tannin extract decreased in vitro digestibility of nutrients both by pepsin hydrolysis or pepsin-pancreatin hydrolysis (P < 0.05). Although enzymatically unhydrolyzed residues provided more energy (P = 0.09) and nitrogen (P < 0.05) as fermentation substrates, the microbial degradation of nutrients from unhydrolyzed residues and porcine ileal digesta were both decreased by sorghum tannin extract (P < 0.05). Regardless of unhydrolyzed residues or ileal digesta as fermentation substrates, microbial metabolites including the accumulative gas production excluding the first 6 h, total short-chain fatty acid and microbial protein content in the fermented solutions were decreased (P < 0.05). The relative abundances of Lachnospiraceae AC2044 and NK4A136 and Ruminococcus_1 was decreased by sorghum tannin extract (P < 0.05). In conclusion, sorghum tannin extract not only directly decreased the chemical enzymatic digestion of nutrients in the simulated anterior intestine, but also directly inhibited the microbial fermentation including microbial diversities and metabolites in the simulated posterior intestine of pigs. The experiment implies that the decreased abundances of Lachnospiraceae and Ruminococcaceae by tannins in the hindgut may weaken the fermentation capacity of microflora and thus impair the nutrient digestion in the hindgut, and ultimately reduce the total tract digestibility of nutrients in pigs fed high tannin sorghum.

Comparative digestion and fermentation characteristics of low-tannin or high-tannin sorghum grain in the porcine gastrointestinal tract

High-tannin sorghum grain (HTS) has been previously proved to contain lower apparent total tract digestibility (ATTD) of nutrients than low-tannin sorghum grain (LTS) for pigs. This study was conducted to identify in which segments (foregut or hindgut) of the intestinal tract of pigs the digestion of nutrients was mostly influenced, and to compare the digestion and fermentation characteristics of LTS and HTS in the porcine gastrointestinal tract. In experiment 1, HTS and LTS were digested by porcine pepsin and pancreatin to simulate small intestine digestion, and subsequently the undigested residues were incubated with fresh pig cecal digesta as inoculums for 48 h to simulate the porcine large intestine fermentation in vitro. The results revealed that the in vitro digestibility of air-dry matter, gross energy (GE), and crude protein (CP) was lower (P < 0.05) in HTS than that in LTS, regardless of the simulated small intestine digestion or large intestine fermentation. The enzymatically unhydrolyzed residue of HTS decreased the accumulative gas production excluding the first 3 h and the short-chain fatty acid concentration including acetic acid, propionic acid, and butyric acid in the fermented solutions (P < 0.05), although it provided more nutrients as fermentation substrates (P < 0.05). In experiment 2, 12 crossbred barrows (25.5 ± 2.5 kg body weight) with a T-cannula inserted in the distal ileum were randomly allotted to two diets (N = 6) to determine nutrient digestibility in the foregut (AID, apparent ileal digestibility) and in the hindgut of pigs (HGD, hindgut disappearance). The study lasted 10 d, with a 5 d adaption to the diets followed by a 3 d collection of feces and then a 2 d collection of ileal digesta. Diets included 96.6% HTS or LTS as the only source of dietary energy and nitrogen. The AID and ATTD of dry matter, GE, and CP in HTS were lower than those in LTS (P < 0.05). There was no difference in HGD of nutrients between LTS and HTS. Eight out of fifteen amino acids in HTS had lower AID values (P < 0.05). In conclusion, HTS provided lower small intestine digestibility of nutrients and lower large intestine fermentation parameters, implying that condensed tannins in sorghum grain may impede the nutrient digestibility in the foregut and limit the fermentability in the hindgut segment of pigs. Hence, digestion and fermentation characteristics of sorghum grain may vary depending on the condensed tannins.

Effects of Brewer Grain Meal with Enzyme Combination on Growth Performance, Nutrient Digestibility, Intestinal Morphology, Immunity, and Oxidative Status in Growing Pigs

This study investigated the effects of supplementing feed with various levels of brewer grain meal (BGM) and enzymes (amylase, xylanase, β-glucanase, lipase, cellulase, β-mannanase, phytase, and pectinase) on growth performance, nutrient digestibility, intestinal morphology, immunity, and oxidative status in growing pigs. Eighty growing pigs were subjected to four feed treatments (five replicates per treatment), based on a corn-soybean basal diet: feeds with 0.1% enzyme combination supplementation (PC), no enzyme supplementation (NC), 20% BGM with 0.1% enzyme combination (BGM20), and 40% BGM with 0.1% enzyme combination (BGM40). Supplementing the feed with both BGM-supplemented diets significantly increased final body weight, average daily gain, the digestibility of crude protein and ash, serum concentration of total proteins, superoxide dismutase activity, villus height in the duodenum and jejunum, and duodenal villus height to crypt depth ratio; however, it did not significantly increase blood urea nitrogen, tumor necrosis factor-alpha, malondialdehyde levels, and duodenal crypt depth compared to the NC diet (p < 0.05). Furthermore, a lower hindgut pH in the middle of the colon was detected following the BGM-supplemented diet compared to PC treatment (p = 0.005). Increased levels of triglycerides and albumin were detected in BGM20-fed pigs, whereas increased levels of glucose, total antioxidant capacity, and glutathione peroxidase but decreased interleukine-6 levels were observed in the BGM40 compared with the NC group (p = 0.05). No differences were observed in the average daily feed intake and gain to feed ratio, in the serum levels of aspartate aminotransferase or immunoglobulins (p > 0.05). The addition of up to 40% BGM combined with 0.1% enzyme supplementation positively promotes the growth performance, nutrient utilization, and intestinal health of growing pigs.