High-tannin Sorghum Grain Research Articles

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.

Ruminal degradation of dry matter and fibrous fraction of high-tannin grain sorghum

The present study aimed to evaluate the effect of replacing corn with high-tannin sorghum grain in the diet of steers on ruminal degradation of dry matter and fibrous fraction. Four rumen-fistulated cattle with a mean body weight of 519 ± 31 kg were used in this study. These animals were divided into groups using a 4 ´ 4 Latin square experimental design. Animals received four different diets in which increasing levels of ground corn were replaced with high-tannin sorghum grain in the proportions of 0%, 33%, 67% and 100% in the concentrate. Dry matter (DM) and neutral detergent fiber (NDF) were measured by in situ incubation of sorghum grain samples. Rumen residue was analysed for DM and NDF disappearance at incubation times of 0, 6, 12, 24, 48, 72, 96, 120 and 144 h. A quadratic behavior was observed in the fraction €œc€ of the DM and soluble fraction "a" of the NDF of the sorghum grain in function of the replacement levels of corn for high-grain tannin sorghum. Rumen DM and NDF degradability of sorghum grains with high tannin content up to 144 h showed an increasing behavior for all levels of inclusion of sorghum in the diet. The replacement level 67 showed the maximum DM and fibrous fraction disappearance of sorghum grain up to 144 h of incubation. Sorghum grain achieved maximum ruminal dry matter degradation and the fibrous fraction at the 67% replacement level of ground corn by high-tannin sorghum grain in the diet of steers.

PSXIV-21 Effect of high-tannin sorghum grain on rumen fermentation and methane production in vitro

Abstract Tannins are natural compounds with potential to reduce enteric methane (CH4) emissions in ruminants. High-tannin sorghum (HTS) varieties are cultivated in different regions of the world, including Mexico. The objective of this study was to evaluate the effects of HTS on rumen fermentation and CH4 production using a batch culture system. The experiment was set up as a completely randomized block design using a 3 × 5 factorial arrangement with 3 grains [HTS, low-tannin sorghum (LTS), and corn, with 19.6, 0.07 and 0 g of condensed tannins (CT)/kg dry matter (DM) respectively] and 5 grain to forage (alfalfa hay) proportions (20:80, 40:60, 60:40, 80:20 and 100:0). Data were analyzed using the MIXED procedure of SAS. Contrasts were used to determine linear and quadratic effects of grain:forage proportions. A decrease of 2.96% in CH4 concentration was observed for sorghum treatments compared to corn (P &amp;lt; 0.01). However, HTS and LTS were not different from each other (P = 0.76). Furthermore, CH4 production (mL/d) decreased (P &amp;lt; 0.01) by 19.13 and 8.53% with HTS compared with corn and LTS respectively. This reduction was associated with a decrease (P &amp;lt; 0.01) of 14.52 and 10.04% in total gas production with HTS as compared to corn and LTS. Both, CH4 and gas production decrease, were associated with reduced DM digestibility for HTS, which can be a negative effect of CT in HTS. Sorghum treatments produced 14.56% less CH4 (mL/g DM; P &amp;lt; 0.01) than corn. This was partially explained by a 7.98% decrease in DMD with sorghum treatments. As expected, gas production linearly increased and rumen pH linearly decreased with increasing levels of grain (P &amp;lt; 0.01). In conclusion, HTS had no advantage over LTS in terms of CH4 production. Nonetheless, sorghum grain, substituted for corn, can be an option to decrease CH4 production in ruminants, but digestibility might be compromised.

Nutritional value of high and low tannin high-moisture sorghum grain silage in horses

The objective in this work was to determine the nutritive value of high and low tannin high-moisture sorghum grain silage in horse feeding by means of digestibility. A total of eight crossbred geldings at the age of six years and an average body weight of 330 kg were used in a complete randomized design with samples replicated on the same animals. The test-diets consisted of the ensiled high and low tannin sorghum grains replacing 30% of the dry matter of the reference diet, constituted exclusively by hay. The daily dry matter intake was equivalent to 2.0% of the body weight, so, the test diets were constituted by 30% of ensiled sorghum grains and 70% of hay. The digestibility coefficients of the nutrients of the low and high tannin sorghum grain silages were obtained by the difference between the coefficient of digestibility of the nutrients of the reference diet and the test-diets. The values of digestibility of dry matter, energy and protein of the high tannin sorghum grain silage were lower (73.65, 73.65 and 71.33%) than low tanin sorghum grain silage (87.70, 87.70 and 82.36%). The contents of digestible dry matter, digestible protein, digestible starch, digestible neutral detergent fiber and digestible energy were 59.08%, 10.63%, 71.48%, 2.32% and 3,954 Mcal/kg of dry matter of the low tannin sorghum grain silage and 50.58%, 8.16%, 67.80%, 3.72% and 3,192 Mcal/kg of the dry matter of high tannin sorghum grain silage, respectively, therefore, only contents of digestible neutral detergent fiber and starch were similar among silages. The use of low tannin sorghum grain silage, an alternative food in formulation of promising diets for horses feeding.

Amino Acid Content and Availability in Low, Medium and High Tannin Sorghum Grain for Poultry

In order to assess and determine amino acids profile and availability in different sorghum grain (SG) varieties, three SG varieties including low tannin (0.09%, LTS), medium tannin (0.19%, MTS), and high tannin (0.37%, HTS) were grown in the same location. The grains were analyzed for their proximate analyses, tannin, and amino acids. True amino acid availability (TAAA) was obtained by caecectomized single comb leghorn cockerels and Sibbald's method. The results showed that the first and the second limiting amino acids in LTS and MTS were methionine and cystine, respectively. Whereas in HTS, lysine (0.166%) was the first and methionine (0.176%) was the second limiting amino acid. Methionine contents in LTS, MTS, and HTS were 0.114%, 0.182%, and 0.176%, respectively. Although crude protein was lower in HTS (10%) than the other SG, histidine, methionine, and isoleucine were higher for HTS as compared to LTS and MTS. TAAA decreased when tannin content increased and all amino acids had a lower availability in HTS than in LTS and MTS (p<0.05). Methionine in HTS and LTS had the highest availability as had glutamic acid in MTS. The availability of proline was most affected by tannin, which was 91.55% for LTS, 84.82% for MTS, and 22.82% for HTS (p<0.05).

In vivo effects of dietary sorghum tannins on rabbit digestive enzymes and mineral absorption

This study demonstrates the extent of the in vivo inhibitory action of two levels of dietary sorghum tannins on rabbit digestive enzymes as well as mineral absorption. Addition of low-tannin (1.4% catechin equivalent) sorghum grains to the animals diet did not significantly change growth rate, food consumption, or feed conversion ratio. However, addition of high-tannin (3.5% catechin equivalent) sorghum grains significantly reduced their live body weight gain, feed conversion ratio, and slightly increased food consumption with respect to the control. The activities of α-amylase, trypsin and lipase in digesta obtained from the upper part of the small intestine were inhibited in animals fed on sorghum grains. Inclusion of low- and high-tannin sorghum grains inhibited α-amylase by 37% and 77%, trypsin by 22% and 56% and lipase by 6% and 43%, respectively. Estimation of apparent calcium and magnesium absorption revealed a decrease in the calcium, but not magnesium, absorption only in animals fed high-tannin sorghum grains. Our in vivo results show a significant effect for ingested dietary sorghum tannins on their first target i.e. the digestive tract, as well as indicating though crudely (increased corrected liver weight) the possible toxic effect of sorghum tannin. The lack of toxicity in animals fed low-tannin sorghum grains may suggest the existence of a threshold-limit.

EFFECT OF ALKALINE STEEPING ON WATER UPTAKE AND MALT QUALITY IN SORGHUM

Condensed tannin-free and high-tannin sorghum grain were steeped in dilute alkali and the effects on water uptake during steeping and final malt quality were determined. With the condensed tannin-free sorghum, steeping in dilute alkali led to increased water uptake during steeping and an improvement in malt quality in terms of diastatic power and free amino nitrogen. These effects are presumed to be due to the alkali opening up the pericarp cell wall structure of the grain, allowing more rapid water uptake. Best results were obtained by application of alkali early in steeping, presumably because the grain is less susceptible to alkali toxicity than later in steeping. Steeping high-tannin sorghum in dilute alkali did not improve malt quality. This appeared to be because water uptake was not increased to the same extent as with condensed tannin-free sorghum, as the alkali reacted with the tannins.

Absorption and Distribution of 14C-Labeled Condensed Tannins and Related Sorghum Phenolics in Chickens

Condensed tannins from sorghum (Sorghum bicolor (L.) Moench.] seeds are the only type of tannins found in this plant and are commonly associated with toxic effects in animals fed diets based on high-tannin sorghum grains. However, it is still not certain whether those polyphenolic polymers are absorbed from the digestive tract. Condensed tannin and other related phenolic fractions from sorghum seeds were metabolically radiolabeled with 14 C and separately fed to Hubbard White Mountain chicks. Their tissues were examined to determine the absorption and distribution of the polyphenolic fractions

Traditional processing of high-tannin sorghum grain in Uganda and its effect on tannin, protein digestibility, and rat growth

In the southern highlands of Uganda and neighboring areas, where high-tannin sorghum [Sorghum bicolor (L.) Moench] types with soft endosperm grains are extensively grown, a unique traditional technology was evolved to process high-tannin grains before they are consumed. This technology, which is simple and uses locally available material, involves mixing high-tannin grains with wood-ash slurry, followed by soaking the grains in water overnight. The grains are then germinated for 3-4 days, dried in the sun, cleaned, and ground into flour. This wood ash treatment is shown to effectively detoxify the grain and improve the nutritional quality up to the level of low-tannin grains. The traditional technology to process high-tannin sorghum is described, and its simplicity and effectiveness in detoxification and nutritional quality improvement are demonstrated.

Detoxification of High Tannin Sorghum Grains

One in vitro and two in vivo experiments were conducted to determine appropriate methodology for and effects of detoxifying Darset, Redlan, and one commercial hybrid brown sorghum grain variety in threonine-deficient and nutritionally complete poultry rations. The detoxification procedure, which involves adding water to sorghum grain to bring dry matter to 70% and subsequent anaerobic incubation at 32 C, removes up to 100% of the chemically detectable tannin. Rate of tannin elimination was dependent upon sorghum grain variety with commercial brown sorghum requiring approximately 3 days longer than the Darset for tannin elimination. Detoxification of high tannin sorghum grains improved (P less than .05) growth rate and feed efficiency dramatically in threonine-deficient, crystalline amino acid-fortified rations; the same process applied to low tannin sorghum grains was without benefit. The desirable effects of this type of grain processing appear to be due to the reduced grain tannin content. Including detoxified sorghum grains in a practical-type broiler ration failed to elicit a weight gain response although feed efficiency was improved by 13% over untreated sorghum and 3% over corn grain. Lack of a gain response was likely due to the excess protein included in the basal diet. This type of grain processing offers an alternative method of reducing sorghum grain tannin content and is likely of greatest value in rations containing marginal indispensable amino acid and protein levels.

Protein quality in cereals and pulses. 2. Influence of polyethyleneglycol on the nutritional availability of methionine in sorghum (Sorghum vulgar Pers.), field beans (Vicia faba L.) and barley.

1. Polyethyleneglycol (PEG 4000) was examined for its influence on relative nutritional value (RNV) and available methionine in sorghum (Sorghum vulgare Pers.), field beans (Vicia faba L.) and barley, as measured microbiologically with Streptococcus zymogenes. The results were assessed in relation to the content of tannins in the test samples. 2. In grain of hybrid sorghum the RNV averaged 87 (range 79--92) for six low-tannin varieties and 41 (30--53) for eleven high-tannin varieties. The corresponding available methionine values averaged 17.0 (15.7--18.9) and 8.9 (6.7--11.0) g/kg protein. Addition of PEG 4000 to the test samples increased the average RNV of the high-tannin varieties from 41 to 78, and the average available methionine content from 8.9 to 16.2 g/kg protein. 3. With seed of ten coloured flowered varieties of field beans, treatment with PEG gave a small but consistent increase in the available methionine content, which resulted from the inactivation of tannins in the testa. 4. In twenty-three samples of barley grain, treatment with PEG had no effect on the values obtained for available methionine. 5. Treatment of high-tannin sorghum grain with ammonia has been reported to inactivate the tannins and increase the nutritional value for rats and chicks. This finding was confirmed. The present study showed that ammonia and PEG 4000 were equally effective in enhancing the nutritional quality as measured in the microbiological tests.

Investigations of Leg Abnormalities in Chicks Consuming High Tannin Sorghum Grain Diets

Studies were conducted into the etiology of leg abnormalities noted in chicks fed high tannin sorghum grain diets. These anomalies were characterized by a bowing of the legs with a swelling of the hock joints. The incidence of these leg problems was found to be markedly higher when the amino acids in the diet provided by soybean meal were replaced by crystalline amino acids. Supplemental vitamins and minerals had no alleviating effect on the leg problem. Bone mineralization was apparently not influenced by tannins as demonstrated by similar bone ash values for chicks fed high or low tannin sorghums. A possible alteration caused by tannin in the organic matrix of bone is discussed.High tannin sorghum depressed chick growth and feed conversion when compared with low tannin sorghum in both sorghum-soybean meal and sorghum-amino acid rations. This growth depression was overcome by supplementing the high tannin sorghum-soybean meal diet with .15% DL-methionine, but no growth response was observed from a similar supplementation of a high tannin sorghum-amino acid diet.