Production of Bacterial and Yeast Biomass in Ground Corn Cob and Ground Corn Stalk Media1

The production of biomass using ground corn cobs and ground corn stalks and a 1:1 (w/w) mixture of the two was studied using Cellulomonas uda in a monoculture and in mixture with Candida utilis. The addition of C. utilis improved the amino acid content of the biomass. With the combination of C. uda and C. utilis, there was more soluble protein in the growth medium. With the addition of C. utilis to the corn cob fermentation, the relative nutritive value increased from 45.7% with a monoculture to 72.6% with a mixed culture. The crude protein also increased from 13.5 g/100 g to 21.1 g/100 g. The ratio of enzyme activity with carboxymethyl cellulose to that of filter paper was about two at the 5th day of fermentation.

Nutritional Improvement of Corn Meal by Fermentation by Bacillus licheniformis and Enterobacter cloacae1

Fermentation of corn meal by Bacillus licheniformis strain 6 significantly (P<0.05) increased the percent relative nutritive value (%RNV). Both B. licheniformis strain 6 and Enterobacter cloacae strain 18 significantly (P<0.05) increased the methionine and tryptophan content. Only E. cloacae increased the lysine content. Both bacteria increased total folacin significantly (P<0.05). A pH of 7–8, a temperature of 35°C, and a fermentation time of 4–6 days resulted in higher yields of total folacin than other combinations of conditions. Mixed cultures of the two bacteria increased lysine, methionine, tryptophan, and total folacin (P<0.05) when compared to nonfermented corn meal.

Mixed Culture Fermentations To Improve Nutritional Value of Corn Meal1

One-step fermentation involving two microorganisms inoculated at the same time and two-step fermentations involving two inoculations of different microbes at different times were used to enrich corn meal. Starch in corn meal was first hydrolyzed by amylases of B. stearothermophilus, E. fibuligera or A. oryzae followed by the growth of C. utilis. The combination of E. fibuligera and C. utilis produced a significant (P<0.05) increase in lysine, methionine, tryptophan. The relative nutritive value (%), which reflected the amino acid balance, increased significantly (P<0.05) with this sequence of microorganisms. Niacin, riboflavin, and thiamin increased significantly (P<0.05) when mixed cultures of A. oryzae and E. fibuligera in combination with C. utilis were employed. When E. fibuligera alone was grown, no significant change was observed in thiamin content but significant increases occurred in niacin and riboflavin. A. oryzae by itself produced significant (P<0.05) changes in niacin, riboflavin and thiamin.

OVIPOSITION AND LARVAL DEVELOPMENT OF THE RED FLOUR BEETLE AND THE RUSTY GRAIN BEETLE ON GROUND AND BALL-MILLED KERNELS OF VARIOUS CEREAL CULTIVARS

Oviposition and larval development of Tribolium castaneum (Herbst) and Cryptolestes ferrugineus (Stephens) were used as criteria of the nutritional value of 28 ground or 29 ball-milled cultivars of two-rowed barley, six-rowed barley, oat, triticale, durum and common wheat for these insects. Oviposition by individual adult T. castaneum, on 28 ground cultivars, was lowest only on Benito wheat and all oat except Terra (hulless). On 29 ball-milled cultivars, Coulter and Medora durum wheat were optimal for egg production while the least number of eggs was produced on Glenlea (wheat), TR 212 and 219 (two-rowed barley), Bonanza and Conquest (six-rowed barley) and all oat. Oviposition by C. ferrugineus on ball-milled cultivars was also optimal on durum wheat and was lowest on all oat. The pattern of egg laying for both species over three 4-d periods varied with the payability and texture of the ground and ball-milled cultivars. Rate of larval development for T. castaneum on three ball-milled oat and three durum wheat cultivars was slower on oat than on durum wheat and C. ferrugineus larvae rarely survived on oat; there were no significant differences among the cultivars of a crop. Environmental indices based on time to pupation and oviposition indicated the relative nutritive value of the various cereals and cultivars to both insect species.Key words: Oviposition, development, Ball-milled, Cereal, Tribolium castaneum, Cryptolestes ferrugineus

COMPARISON OF MALE STERILE CORN AND REGULAR CORN AS SILAGE FOR DAIRY COWS

The relative nutritive value of male sterile corn silage (23.7% dry matter) and regular corn silage (26.5% dry matter) was determined with lactating dairy cows during three consecutive crop years. The regular corn hybrid had 25% of the kernels removed by black birds prior to harvesting. Grain was fed according to milk production (1 kg/2.75 kg milk) and silage was offered ad libitum as the only forage. Dry matter, soluble carbohydrate and insoluble nitrogen percentages were lower while crude protein and acid detergent fiber levels were higher in the male sterile corn silage. Apparent digestibilities of dry matter, nitrogen and energy determined with sheep were not different between silages. Silage dry matter intake and total dry matter intake were higher (P < 0.05) for cows fed regular corn silage in only one of the three trials. Actual milk, 4% fat-corrected milk yields and milk fat and protein percentages were not affected by silage treatment. Key words: Male sterile corn, silage, dairy cows