Digestibility Of Maize Research Articles

Effects of temperature during different stages of development on growth and digestibility of forage maize (Zea mays L.).

Growth and digestibility of forage maize were studied when it was exposed to low (18 degrees C day/12 degrees night) or high (30 degrees /24 degrees ) temperatures during the following periods of development: from sowing to the 8-leaf stage; from the 8-leaf stage to grain set; during grain filling. Organic matter digestibility values ranged from 69.5 to 74.1 and differences were caused by differences in cell-wall content and in cell-wall digestibility. Differences were greatest around anthesis but declined thereafter. High temperatures during the period from 8-leaf stage until grain set were most effective in reducing the digestibility. Final amounts of indigestible cell wall were similar for all treatments. Amounts of cellular contents varied only slightly. Amount of truly digestible cell wall was reduced by high temperatures during vegetative growth. Differences in proportion or digestibility of plant fractions resulted only in small differences in whole-plant digestibility. Temperature affected digestibility much less than it affected yield. High temperatures were needed for a prolonged period to obtain a noticeable reduction of digestibility. (Abstract retrieved from CAB Abstracts by CABI’s permission)

Protein quality and amino acid‐protein relationships of maize, sorghum and rice grain as influenced by nitrogen, phosphorus, potassium and soil moisture stress

AbstractIn pot and field experiments cereals were grown with greatly differing rates of N, P and K applications. For maize and sorghum, soil moisture levels were also varied. N applications, P‐ and K‐deficiency, and moisture stress generally increased the total N content of grain, from 1.06 to 2.68, 1.01 to 2.42 and 0.81 to 2.33% (as % of DM) for maize, sorghum and rice, respectively. P, K and moisture stress affected the amino acid composition only indirectly through their effects on N concentration. In all three cereals increasing N concentrations were associated with decreases in crude protein of lysine, methionine, cystine, threonine, tryptophan and, generally, with increases of isoleucine, leucine, phenylalanine and glutamate. Lysine as a percentage of dry matter increased up to the highest N concentration in all three cereals. Linear regressions with significant correlation coefficients were found between concentrations of most (g 16 g−1 N) or all (mg 100 g−1 DM) amino acids and N content of grain. Based on all experimental data equations for lysine were: g 16 g−1 N=4.44–0.89 × %N; 4.23–0.86 × % N; 4.39–0.42 × % N for maize, sorghum and rice, respectively. Correction of P‐ and K‐deficiency decreased N content of grain and resulted in higher lysine content and better nutritional value of grain protein, whereas correction of N‐deficiency had the opposite effect. The amino acid composition of rice was much more balanced than that of maize and sorghum with a leucine/isoleucine ratio of 2 compared to that of 3 in maize and sorghum. In rat feeding experiments true digestibility of maize and sorghum protein was high (about 95%) but increased only slightly with increasing N in grain, whereas the biological value decreased considerably, from 63 to 55 and from 70 to 58, respectively. The chemical score underestimated the nutritional value of both cereal proteins.

Nutritional study of jelawat, Leptobarbus hoevenii (Bleeker), fed on pelleted feed

The digestion coefficients of the nutrients in the ingredients used in formulating the diet (MARDI-37%) for the culturing of jelawat were evaluated. Cr 2O 3 was used as an internal marker for the evaluation of digestibility. The results indicate that jelawat can digest 100% of the protein, fat, carbohydrate and gross energy in fish meal, but only 69.50% protein, 60.70% fat, 73.82% carbohydrate and 59.30% gross energy in soyabean meal. Surprisingly, this fish can digest copra cake meal, an agricultural by-product in Malaysia, better than soyabean meal; the values were 75.36% protein, 98.36% fat, 50.03% carbohydrate, and 73.21% gross energy. Digestibility of maize, rice bran and tapioca was poor in this fish. There were no significant differences in the digestibility of dry matter, protein, fat, carbohydrate, ash and gross energy of the reference diet in jelawat specimens whose total length was greater than 12 cm, whereas in fish smaller than 12 cm digestibility was significantly lower.

Measurement and prediction of digestibility of forage maize in The Netherlands

Results of digestibility trials on fresh and ensiled maize (aerial parts) were analysed and compared with laboratory data. Digestibility of the organic matter of ears was almost constant at 84–85%. Digestibility of organic matter of stover showed great variation. Variation between animals in apparent digestibility of organic matter was greater for maize diets than for diets based on grass products. Most of the differences between animals were caused by differences in the digestion of cell walls. When the true digestibility of cell contents was assumed to be complete, endogenous excretion was, on average, only 7% with respect to organic matter intake, and seemed dependent on digestibility of organic matter. Prediction of apparent digestibility was more accurate with digestibility in vitro than with crude fibre, although for maize silage, significant relationships were found between crude fibre content and digestibility of organic matter. Standard deviation of organic matter digestibility between lots of fresh and ensiled maize grown on commercial farms amounted to only about 1.2 –2%. As this was only twice the accuracy of digestibility in vivo with four animals, fixed values will be presented to farmers, possibly corrected for year, hybrid selection and cropping practice.

Growth, mineral composition and digestibility of maize, sorghum and barnyard millets at different temperatures

Barnyard millets (Echinochloa utilis and E. frumentacea), maize (Zea mays) and a sorghum hybrid (Sorghum bicolor x S. sudanense) were grown as spaced plants at temperature regimens from 15/10 to 33/28�C (dayhight). Leaf and stem dry weight, leaf area and leaf number were recorded every 2 weeks and the dry matter analysed for nitrogen, sulfur, sodium and in vitro digestibility. Tolerance to low temperatures was in the order maize > E. utilis >sorghum >E. frumentacea. At mean temperatures above 25�C, relative growth rates were similar for all species. Differences in leaf area, for which individual leaf size was mainly responsible, accounted for most of the dry weight responses to temperature, although net assimilation rate responses were also apparent. The dry weight response to temperature became negligible after adjusting for differences in stage of development. Dry matter digestibility decreased with temperature; it also decreased with time because of deteriorating stems, except in sorghum. Maize leaves were of low digestibility, similar to stems. The nitrogen : sulfur ratio of all species remained steady with age; in sorghum at low temperature it exceeded the 15: 1 maximum considered desirable for animals. Sodium was highest in E. utilis stems and increased with temperature, in contrast to sorghum. Maize had a marginal nitrogen: sulfur ratio and unacceptably low sodium concentration. It was concluded that more attention should be given to E. utilis as a forage for cool climates.

In vitro Digestibility of Hydroxypropyl Maize, Waxy Maize and High Amylose Maize Starches

AbstractHydroxypropyl derivatives of maize, waxy maize and high amylose maize starches were prepared and characterized. The in vitro digestibility of the raw and gelatinized starches and their derivatives was compared using porcine pancreatic α‐amylase. Digestibility of the unmodified starches decreased in the order waxy maize > maize > high amylose maize. Increasing molar substitution (MS) caused a decrease in digestibility for all starch types after gelatinization. Raw maize and high amylose maize starch derivatives showed an initial decrease in digestibility followed by increases at higher MS levels. The digestibility of the raw waxy maize starch derivatives showed a continuing drop as MS increased.

Effect of the Brown Midrib‐3 Allele on Early Vigor and Growth Rate of Maize1

The brown midrib‐3 mutant (bm3) improves the ruminant digestibility of maize (Zea mays L.) sotver, but homozygous bm3 plants are usually less vigorous than normal plants. Because early season vigor can influence final grain and stover yield, our objective was to investigate the potential for genetically improving the early vigor of bm3 genotypes relative to normal genotypes. A total of 130 bm3 and 130 normal S1 lines were developed from three populations segregating for the bm3 allele and were evaluated in three field environments in Minnesota. Average seedling dry weight of the normal lines was 10% higher than the bm3 lines, but a few bm3 lines had seedling dry weights as high as the best normal lines. Predicted gains from selection among bm3 lines were similar to normal lines of the same population. Dry matter accumulation rates of the normal lines during vegetative growth averaged 13% higher than the bm3 lines, but a few bm3 lines had rates as high as the best normal lines. Two bm3 and two normal S1 lines and their hybrids within bm3 and normal genotypes were evaluated for dry matter accumulation rate over the entire growing season. The average linear accumulation rate of total dry matter was 15% higher in the normal genotypes. The lower rate of grain filling of the bm3 genotypes was somewhat compensated for by a longer effective duration of grain filling. Our results suggest that bm3 populations could be improved to acceptable levels of early vigor and growth rate.

YIELD, QUALITY AND DEVELOPMENT OF FORAGE MAIZE AS INFLUENCED BY DATES OF PLANTING AND HARVESTING

The effects of dates of planting and harvesting on yield, quality and development of forage maize were investigated in a 3-yr study. Treatments studied were all possible combinations of five planting dates, spaced at 2-weekly intervals from late April to mid-June, and three harvest dates (mid-September, early and mid-October). Between early May and mid-June, each 1-day delay in seeding resulted, on average, in a 1% reduction in whole-plant digestible dry matter yield. In vitro dry matter digestibility was not significantly affected by date of harvesting but was reduced progressively from 66 to 63% as the date of planting was delayed. Although grain content varied from 0 to 50% of whole-plant dry matter, it had little effect on the in vitro digestibility of forage maize, which only ranged from 62 to 68%, when whole-plant dry matter contents were acceptable for direct ensiling. During the grain-filling period (450–1600 corn heat units after mid-silking), whole-plant dry matter content (%) was linearly related to accumulated corn heat units (r2 = 0.83***); each 1% increase in dry matter content requiring an input of 40 corn heat units. Thus, using information on the date of mid-silking and daily air temperature records (long-term or current), it is possible to predict the date (average or actual) when whole-plant DM content reaches any desired magnitude for harvesting.Key words: Quality, planting date, harvest date, maize, corn, development

The Effect of Calcium Ions on the Hydrolysis of Starch

AbstractThe ability of raw and dioxan extracted maize and potato starches to bind calcium is shown to influence the in vitro digestibility of the starches using pancreatic α‐amylase. The in vitro digestibility of commercial and fractionated glucose syrups in the presence of calcium is also described. Whilst the extraction process improves the digestibility of both maize and potato starches the addition of calcium lowers the digestibility of raw maize starch. Both raw and extracted potato starch digestibility are increased by the addition of calcium however. When raw and extracted maize and potato starches are converted to glucose syrups by an acid hydrolysis no differences are found in the reducing capacities of the syrup produced.

Effect of the amount and form of roughage in the diet on digestibility of whole maize grain in cows and steers

SUMMARYFour experiments investigated some of the factors affecting the digestion of whole maize grain in non-lactating cows and yearling steers. With steers, but not cows, maize in diets containing small amounts of hay (14%) and large amounts of whole grain were better digested than those with 37 or 48% hay. The higher digestibility of maize in steers was associated with a greater time spent ruminating per kg feed and a longer retention time of maize in the gut than in cows. Replacing long roughage with ground and pelleted roughage in diets for steers improved the digestion of whole maize but not as well as reducing the hay to 14% of the diet. Finely grinding the maize produced a large increase in digestibility of the feed in cows and steers and both digested it to the same extent. It was concluded that the motility of the reticulo-rumen during eating and ruminating largely determines the extent of the digestion of whole maize grain.

Energy Values of Corn, Bird-Resistant and Non-Bird-Resistant Sorghum Grain in Rations Fed to Steers

Three Aberdeen-Angus bullocks were used in a Latin square design to estimate metabolisable energy (ME) and digestibility of maize, bird-resistant (BR) and non-resistant (NBR) sorghums. The diets had 78% of the grains, 16.5% forage sorghum silage and 5% of a supplement consisting of soya bean oilmeal 76%, urea 7% and minerals, vitamins, antibiotic and trace elements. Cattle in the metabolism phase of the experiment were rotated to new rations every 19 days, allowing 14 days for adjustment and 5 days for collection. Production of methane and its energy content were measured. In the feedlot phase, 54 bullocks were fed to appetite or restricted to allow about half the daily gain with feeding to appetite. From each of the 6 groups 1 bullock was killed at the start. The remainder were given 36 mg diethylstilboestrol. The cattle were fed for 128 days. Tannins were estimated in the diets.Bullocks on the restricted amounts of maize, NBR and BR gained 62, 66 and 67% of gain with feeding to appetite. The maize, NBR and BR sorghum had 3.21, 2.63 and 2.49 Mcal ME/kg DM. Net energy for maintenance was 2.40, 1.98 and 1.78 Mcal/kg and for gain (NEg) was 1.49, 1.15 and 0.73 Mcal/kg DM when cattle were fed to appetite. Gross energy (GE), ME, NEm and NEg were used to predict gains, using the NRC (NAR 41, 1510) and ARC (NAR 36, 5513) systems and values were compared with actual gains. Predicted daily gains by the NRC system for bullocks fed to appetite agreed within 0.08 kg and by the ARC system were within 0.01, 0.23 and 0.12 kg of actual gains with maize, NBR and BR. When NRC NEm and NEg values for sorghum grain were used for BR, predicted daily gains were 0.45 kg greater than actual gain

The apparent digestibility of maize grain when given in various physical forms to adult sheep and cattle

SummaryA series of digestibility trials was conducted with non-lactating cows and adult castrated male sheep given diets of hay and dried or high-moisture maize grain in various physical forms. Sheep were able to digest all forms of maize well and to a greater extent than cows. In cows considerable variation in digestibility of maize was associated with the particle size of the maize and the individual animal. Maximum digestibility of dried maize in cows ensued when the modulus of fineness lay within the range 4·7–3·0 and with high moisture maize from 5·4 to 5·1. A study was made of the effect of particle size on the rate of digestion of maize suspended in nylon bags in the rumen. Evidence was presented showing the importance of rumination in ensuring the digestion of intact kernels. Possible causes of differences between cows in their ability to digest intact maize kernels are discussed.

Climate, nitrogen and grass. 4. The influence of age on chemical composition and in vitro digestibility of maize (Zea mays L.) and tall fescue (Festuca arundinacea Schreb.).

In a field experiment with maize it was found that in vitro digestibility of leaves decreased somewhat during undisturbed growth, whereas digestibility of stems decreased appreciably. This decrease in leaf digestibility was caused by a lower digestibility of later-developed leaves and by a slight decrease in digestibility during ageing of each individual leaf. In a pot experiment with tall fescue grown at 15/10, 20/15 and 25/20 deg C, it was found that a higher temperature resulted in higher concentrations of cell-wall constituents and lower digestibility, whereas during ageing the percentage of cell-wall constituents remained constant or even decreased, digestibility decreasing slightly. Results suggested that in a constant climate the effect of age on digestibility would be small, and that the great effect of age on forage quality in spring is mainly due to rising temperature and stem formation. (Abstract retrieved from CAB Abstracts by CABI’s permission)

Serum Amylases, Isoenzymes, and Pancreatitis I. Effect of Substrate Variation

Abstract Four plant starches were used to study human amylase activity in normal serum and urine, "pancreatitis" serum, duodenal fluid (secretin stimulated), saliva, and pancreatic extract. The starches were derived from waxy maize, high amylose corn, potato, and corn (pearl), and were lintnerized. It was shown that the rate of digestion of starch by each of the fluids tested depends on the plant starch selected as substrate. Digestion of waxy maize was most rapid. The advantages of using waxy maize as a substrate are indicated as a means of markedly enhancing the sensitivity of serum amylase determination. It was also found that normal serum, urine, and saliva digested potato starch at a greater rate than corn starch with few exceptions, while pancreatitis serum, secretin-stimulated duodenal fluid, and pancreatic extract digested corn starch at a greater rate than potato. These findings suggest that organ-specific amylases exist, and that plant starches might be used to distinguish them.

Digestion trials with swine: II. Comparative determinations of the digestibility of dry-fed maize, soaked maize, cooked maize and flaked maize

In Table XII is given a summary of the mean digestion coefficients obtained in the foregoing maize feeding experiments.The figures in Table XII bring out very clearly the effect of preliminary treatment on the digestibility of maize. An inspection of the dry matter digestion coefficients reveals the fact that maize meal possesses the lowest digestibility when fed in the dry condition, a higher value when fed after thorough soaking in water and a higher value still when first submitted to cooking.These facts are in accordance with anticipation; the surprising feature of the results, however, lies in the discovery of the inappreciable extent to which the maize digestibility is raised by soaking or cooking. A relatively low degree of digestibility might justifiably have been anticipated for raw unsoaked maize, since the hard flinty nature of the grain, even after crushing, might render it liable to be excreted in appreciable amount into the faeces without having been much affected by digestive enzymes. This proved by no means to be the case. The effect of thoroughly soaking the grain prior to feeding was merely to raise the digestibility of the maize by 1 per cent, (from 85·9 per cent, to 86·9 per cent.), whilst even efficient cooking only brought about a rise in digestibility from 85·9 to 88·1 per cent., although, as will be noted by reference to an earlier part of this communication, the conditions of the trial were weighted in favour of the cooked meal by using fine meal for cooking and crushed maize for dry-feeding.

Digestion trials with swine: III. The digestibility of a coarse grade of middlings

In the foregoing communication on maize digestibility (i), reference has already been made to the early difficulties which arose as a consequence of attempting to make measurements on rations consisting wholly of maize and milk. During, the period in which a mixture of milk and flaked maize was being fed, the pigs developed constipation troubles, due, as subsequent results proved, to the almost complete digestion and assimilation of the ration by the animals. At the time, however, it was deemed expedient to alter somewhat the scheme of the experiment and to feed the maize along with a definite weight of coarse middlings. In this manner it was anticipated that the fibre of the coarse wheat offal would promote peristaltic activity in the intestinal tract and thus assist the passage of undigested food residues.The introduction of the middlings into the experimental ration made necessary the determination of the digestibility of this feeding stuff. The results of this trial are given for convenience in this separate communication.

Digestion trials with swine: IV. Note on the utilisation of whole milk by swine

During the investigation in connection with maize digestibility recorded in the current issue of this journal (1), a period of feeding was carried out in which the two pigs received a ration consisting of unsoaked crushed maize and whole milk. Although it was found necessary to discontinue the main maize trial along these lines, the results of this isolated period are not without interest, since they enable conclusions to be drawn concerning the extent of the digestion and assimilation of the constituents of milk when fed to swine.The crushed maize used in this period was from the same stock as that fed in the mixed maize and middlings periods. The daily ration consisted of 2000 gm. crushed maize together with one quart of whole milk; it was given in two equal portions during the day, the milk and a little water being mixed with the dry maize in the trough at the time of feeding. The presence of the milk appeared to make the ration attractive to the animals, since ready and complete consumption was obtained.