A study was conducted to develop a new analytical method to quantitate chicken dietary fiber (CDF). Four types of grain diets and 2 types of forages were used. Three broiler chicks at eight weeks of age were used in the Latin square design to estirnate the in vivo digestibility. Six quantitative analytical methods (Southgate method, total dietary fiber or TDF, acid detergent fiber or ADF, neutral detergent fiber or NDF, crude fiber or CF) including CDF were compared in this study. ADF, NDF and CF contained the lowest amount of the unavailable carbohydrate(UC). The value of TDF was higher than the values of ADF, NDF and CF and lower than CDF and the Southgate method. The value of NDF showed the lower values than the CDF, Southgate fiber and TDF. The recovery rate of the fiber in the feces was high in the TDF, ADF, NDF and CF, while CDF and Southgate fiber showed lower recovery rates. TDF, NDF, ADF, or CF can replace chromium in the digestibility test, while the CDF and Southgate fiber can not replace chrorniurn. The digestibility of TDF, NDF, ADF and CF in the chicken showed negative values or values close to zero depending on the types of feed but the digestibility of CDF and Southgate fiber showed relatively high positive values.

In order to study performance enhancing effects of supplementary antibiotics (avoparcin, nosiheptide and enramycin), two feeding trials were conducted. In Experiment 1, 1, 040 male Arbor Acres were reared in floor pens for 6 wk. Chicks were assigned to one of the following four treatments: Basal diet(B), B+avoparcin 10 ppm, B+nosiheptide 2.5 ppm and B+enramycin 5 ppm. Each treatment had five replications of 52 chicks each. In Experiment 2, two antibiotics (avoparcin and enramycin) were compared in $2{\times}2$ (antibiotics$\times$sex) factorial design. One thousand broiler chicks were reared in floor pens for 6 wk. Each of the 4 treatments had five replications of 50 chicks each. The results of Experiment 1 showed that antibiotic treatments (enramycin, avoparcin and nosiheptide) significantly(P <0.05) improved weight gain. Feed/gain ratio of avoparcin treatment and enramycin treatment tended to he lower than the control but they were not statistically significant. Dressing percentages were high in avoparcin and enramycin treatments compared to the control and nosiheptide treatment. The number of E. coli and Cl. perfringens in ileum and cecal contents were decreased by antibiotic treatments. Moisture contents in excreta of the birds were not significantly affected by the treatments. Leg abnormality and mortality were not significaniy different among treatments. In Experiment 2, weight gain was significantly (P<0.01) different between sexes, but not between antibiotic treatments. Significant effects of antibiotics (P<0.01), sex (P<0.01) and interaction (P<0.05) were shown in feed in take. Feed/gain ratio of avoparcin treatment was significantly (P<0.01) lower than that of enramycin treatment. leg abnormality and mortality were not significantly different among treatments but those in male broiler tended to be higher than in female broilers. It was concluded that nonsystemic antibiotics supplemented to the broiler diets suppress undesirable microorganisms and improve broiler performace in general and avoparcin was most effective in improving feed/gain ratio.

Chickens subjected to heat stress decrease their heat production by consuming less feed. The lowered feed intake naturally brings about decreased production performance of chicken. The only exception to this is the increased survivability. Birds drink less when they eat less. In hot enviror-mental temperature, chicken need more water for increased heat loss through evaporation an increased urine excretion. Thus, the increased water intake may alleviate the heat stress of chicken. Various electrolytes supplementation to feed or drinking water can alleviate the heat stress of chicken by their effect of increasing water intake. Lasalocid, an ionophorous coccidiostat, was found to have the effect of increasing water consumption of chicken, thereby improving the lowered production performance of heat-stressed chicken. Finally, dietary fiber could be another possible element which can exert beneficial effects on heat-stressed chicken.

From the observations of dietary self-selection by growing pullets, step-up protein or reverse protein and single-stage low protein pullet feeding systems were developed. They offered another pullet feeding concept that appears to control the body weight effectively and to reduce the consumption of feed and nutrients without impairment of subsequent laying performance. It is obvious from the feed and nutrient consumption pattern of layers fed diets for self-selection of energy, protein and calcium that they have a daily cyclic requirement rather than a constant requirement for nutrients. It seems that a practical self-selective feeding system is needed to meet the daily cyclic requirement for nutrients without consuming an excess of energy and protein at certain times of the day as compared to the complete or single diet where layers have to consume extra energy and protein in the afternoon when they have a specific appetite mainly for calcium.

Of the 200, 000 known species of molds, only 50 or 60 are known to be harmful to humans or livestock. Certain fungi that grow on grains and grasses can produce chemical substances called mycotoxins that adversely affect performance in poultry. There are several methods of preserving feed ingredients. The list includes: drying, antioxidants, mold inhibitors, organic acids, phosphates, cooking or toasting, fat extraction, blending and fermenting. Mold inhibitors are manufactured to inhibit mold growth and prevent the production of toxic substances. They are fungistats and not fungicides, that is, they only stop the growth of molds. Practical and cost-effective methods to detoxify mycotoxin containing feedstuffs are in great demand. 0.5% hydrated sodium calcium aluminosilicate added to the diet protected chicks from the deleterious effects of aflatoxin-contaminated feed. The dietary addition of antioxidants and methionine also significantly diminished the negative effects on body weight in chicks toxicated with 3.0 ppm aflatoxin B1.

The physiological functions of drinking water in chicken were reviewed. The effects of ambient temperature, humidity, wind velocity, egg productivity, feed form, nutrients density, and breed types on the water consumption of chicken were summarized and discussed. Some guidelines for management of drinking water in commercial poultry farms were also suggested.

A study of concurrent bioassay for protein quality and energy level in protein sources was rnade by determining urinary nitrogenous compounds in excreta. The carry over effect of previous feeding was eliminated by 48 h of feeding the experimental diets prior to the determination of for protein digestibility and utilizability, and energy digestibility and metabolizability at 24 h interval during 3 days. Then, protein qualities and energy levels for soybean meal, rapeseed meal and fish meal were calculated by a substitution method. Apparent protein utilization (NB/NI) was affected by the increased fecal nitrogen excretion in soybean meal and by the increased urinary nitrogen excretion in rapeseed meal and fish meal. The apparent metabolizability of energy (ME/GE) was affected by the fecal energy excretion in soybean meal and rapeseed meal and by urinary energy excretion in fishmeal. The results indicated that the concurrent bioassay of protein quality and energy levels in ingredients appears to be applicable to chickens of other age, sex, breeds and environmental conditions.

Egg cholesterol has been a hot issue in respect of it's effect on health and diseases in human. There is a general recognition that the cholesterol from eggs is similar to that from the other dietary sources in its biochemical functions. Many evidences show that egg yolk increased plasma cholesterol levels at an average rate of 2.3 mg /100 rnL plasma for every 100 mg cholesterol consumed. The elevation of plasma cholesterol could, however, be altered by various dietary factors such as ratios of polyunsaturated fatty acids and saturated fatty acids. Blood cholesterol levels of Korean adults have been raised up to, on the average, 193 and 187 mg /100 mL plasma for men and women, respectively, from 167/5 mg /100 mL in 1980. Furthermore, proportion of hypercholesterolemics(> 210 mg /dL) has been increased up to 23% of the population. These changes in blood cholesterol levels are attributed to the changes of dietary patterns, suggesting the arguement that Koreans are insensitive to changes of blood cholesterol is not right. Egg cholesterol levels have never been successfully reduced to any significant levels even with tremendous amounts of efforts made during last decades. The alternative and the best way to control blood cholesterol level originating from egg consumption appeares to enrich egg fat with omega-3 series fatty acids. Ingestion of the fatty acid group has specific functions to reduce hypertension and prevent various types of cancer as well as to reduce blood cholesterol. Another way to reduce egg cholesterol directly is to produce smaller egg yolk without reducing whole egg size since cholesterol is located only in the yolk. It is important to keep faith with consumers by providing correct informations on eggs, meanwhile efforts need to focus on to improve the quality of eggs as one of the best protein food items.