To understand the role of lipid metabolism in increasing body fat accumulation after caponization of male chickens, trials were conducted to determine the effects of levels of testosterone implantation on lipoprotein composition. Male chickens were caponized at 12 wk and selected at 16 wk for a 10-wk feeding experiment. Fifteen male and 15 caponized (capon) chickens were used in trial 1. Ten sham operated chickens (sham) and 40 capons were randomly divided among 4 treatments in trial 2; the treatments were as follows: implantation of cholesterol (1.62 mm i.d. x 3.16 mm o.d., 9.24+/-0.36 mg) or implantation of testosterone at low (1 mm i.d. x 3 mm, o.d., 5.88+/-0.23 mg), medium (1.62 mm i.d. x 3.16 mm, o.d., 9.81+/-0.17 mg), or high (2 mm i.d. x 4 mm, o.d., 16.7+/-0.24 mg) dose. The results of trial 1 showed that caponization decreased (P < 0.05) blood testosterone concentrations and increased (P < 0.05) abdominal fat weight and relative abdominal fat weight in capons. Caponization also increased low density lipoprotein (LDL), high density lipoprotein (HDL), LDL protein, and HDL protein and decreased LDL-free cholesterol (LDL-FC), HDL-FC, and HDL-phospholipid (HDL-PL) percentages (P < 0.05). In trial 2 capons implanted with increasing testosterone levels exhibited proportional increases in blood testosterone concentration, although blood testosterone concentration in implanted capons were not fully restored to those of the sham group. High dose testosterone implantation inhibited abdominal fat accumulation and increased glucose and glycerol concentrations compared with the cholesterol implantation. Caponization of male chickens decreased the androgen level and increased the blood triacylglyceride content. Caponization also changed the lipoprotein profiles, which resulted in increased lipid storage capacity. The testosterone concentration, therefore, must achieve threshold concentrations to inhibit lipid accumulation in the testosterone implanted capon.

Bacillus subtilis var. natto N21 (Bac; for greater proteolytic capacity) and Saccharomyces cerevisiae Y10 (Sac; for greater acidic capacity) were applied to produce a 2-stage combined fermentation feed. This study investigated whether the enhancement of Bac+Sac fermented feed on broiler growth performance was due to the probiotics per se or due to the fermentation process. Trial 1 included 1-d-old broiler chicks (n=144) randomly assigned to control, water added (same as in the fermentation feed, 23%), and Bac+Sac fermented feed (FBac+Sac) treatments with 4 replicates. Trial 2 included 21-d-old broiler chickens (n=12) assigned into control and FBac+Sac groups for a metabolic trial for nutrient availability. Trial 3 included 1-d-old male broiler chicks (n=216) randomly assigned into 6 treatments with 3 replicates. Treatments included a control, Sac fermented feed (FSac), FBac+Sac, Bac powder (PBac), Sac powder (PSac), and Bac+Sac powder (PBac+Sac). The results from trial 1 showed that FBac+Sac increased BW and feed intake (P<0.05) in 21- and 39-d-old chickens. The water-added group showed decreased BW, weight gain, and feed intake (P<0.05). Trial 2 showed that FBac+ Sac increased gross energy availability (P<0.05). Trial 3 showed that FBac+Sac increased 21- and 39-d-old BW and weight gain (P<0.05). Diets supplemented with probiotic powder or fermented with Sac did not improve broiler growth performance (P>0.05). The growth performance improvement of the FBac+Sac treatment was probably not due to the added water, probiotic powder inclusion, or through single-strain fermentation, but due to the 2-stage fermentation process using Bac and Sac strains.

This trial was designed to study the caponization effects on the appearance, carcass characteristics, blood constituents and lipid metabolism of Taiwan country chicken cockerels. Cockerels were caponized at 8 weeks of age. Sixteen-week-old chickens, including 10 capons, 5 slips (incomplete caponized male chickens) and 20 normal chickens of equal sexes were selected for a 10 week ad libitum feeding trial. Results showed that the testosterone concentrations in the capons and females were lower (p<0.05) than that of intact males. The comb length, height and weights were also lower (p<0.05). The weight of the slips was between that of the capons and intact males, but was heavier (p<0.05) than that of the capon. The live-weight, carcass weight and shank perimeter in the capons were higher than those of the other groups (p<0.05). Hepatic lipogenic enzyme activity analyses showed that NADP-malic dehydrogenase (MDH) activity in the capons and female chickens was higher than that in intact male chickens (p<0.05). The MDH activity in the slips was between that for the capon and intact male chickens (p>0.05). The abdominal fat weight and relative abdominal fat weight of the capons and females were heavier than that for intact males (p<0.05); the slips were between the capons and intact males. The blood lipid content results showed that the triacylglycerol and cholesterol in the capons were higher than that for intact males (p<0.05). However, the percentage of low-density lipoprotein (LDL) was lower than that in intact male chickens (p<0.05). It appears that the increase in lipid accumulation in caponized male chickens is attributed mainly to an increase in MDH activity and the changes in lipid transportation in the capons.

The effects of caponization and androgen implantation on the bone characteristics of male chickens were evaluated. Healthy Single Comb White Leghorn cockerels were caponized or sham operated (sham) at 12 wk old. Sixteen birds from each group were selected for a 14-wk experiment in trial 1. Sixteen birds from the sham group and 64 from the caponized group (randomly allocated into 4 treatments) were implanted with 10.4 +/- 0.4 mg (1.62-mm i.d., 3.6-mm o.d.) of cholesterol, testosterone (TES), 5alpha-dihydrotestosterone (5alpha-DHT), or 19-nortestosterone (19-NorT) and were assigned to trial 2 for a 14-wk experiment. The results from trial 1 showed that caponization increased BW (P < 0.05) and decreased tibia stress, ash content, and P content with higher blood P concentration (P < 0.05) as compared with the sham group. In trial 2, the cholesterol implantation group showed the lowest tibia breaking strength, bending moment, stress, and ash content (P < 0.05). The 19-NorT implantation group showed decreased (P < 0.05) blood Ca and P concentration but increased tibia ash and P content, reaching the same level as the sham group (P > 0.05). The adverse effects of caponization on bone characteristics could be improved using androgen implantation. Among the implantation groups, the 19-NorT implantation group showed the best improvement in tibia breaking strength and bending moment, followed by the TES and 5alpha-DHT groups. The TES group showed the best improvement in tibia stress, followed by the 19-NorT and 5alpha-DHT groups.

Bacillus subtilis var. natto N21 (BS) and different lactic acid bacteria were applied to produce two-stage fermented feeds. Broilers were fed these feeds to select the best fermented feed. The selected fermented feed was pelleted and investigated for its effects on growth performance, carcass traits, intestinal microflora, serum biochemical constituents, and apparent ileal nutrient digestibility. Trial 1 involved three hundred thirty-six 1-d-old broilers with equal numbers of each sex, randomly assigned into control, BS + Bacillus coagulans L12 (BBC), BS + Lactobacillus casei (BLC), BS + Lactobacillus acidophilus (BLA), BS + Lactobacillus acidophilus L15 (BLA15), BS + Lactobacillus delbruekckii (BLD), and BS + Lactobacillus reuteri P24 (BLR24) groups with 3 replicates per group. Trial 2 involved two hundred forty 1-d-old broilers with equal numbers of each sex, randomly assigned into control, BBC, and pelleted BS + Bacillus coagulans L12 fermented feed (PBBC) groups with 4 replicates per group. Trial 3 involved sixteen 21-d-old male broilers randomly assigned into control and PBBC groups with 4 replicates per group for a nutrient digestibility trial. The feed conversion ratio (FCR) in the BBC group was better than the control (P < 0.05), and the production efficiency factor (PEF) was the best. However, weight gain (WG), feed intake (FI), and PEF were the lowest in the BLD group (P < 0.05). The WG during 0 to 21 d and 0 to 35 d in the PBBC groups were higher than the control (P < 0.05). The relative weight of the proventriculus + gizzard in the BBC and PBBC groups were higher than the control (P < 0.05). The digestible amino acid content in the PBBC group increased significantly (P < 0.05). Bacillus coagulans L12 is the best lactic acid bacteria for second stage fermentation. PBBC improved broiler growth performance, which may be due to the higher digestible amino acid content, it has the potential to become a commercial feed.