Numerical and experimental studies of water disinfection in UV reactors.

Performance of UV reactors for water disinfection is investigated in this paper. Both experimental and numerical studies are performed on base reactor LP24. Enterobacteria phage MS2 is chosen as the challenge microorganism in the experiments. Experiments are conducted to evaluate the effect of different parameters, i.e. flow rate and UV transmission, on the reactor performance. Simulation is carried out based on the commercial software ANSYS FLUENT with user defined functions (UDFs) implemented. The UDF is programmed to calculate UV dose absorbed by different microorganisms along their flow trajectories. The effect with boundary layer mesh and without boundary layer mesh for LP24 is studied. The results show that the inclusion of boundary layer mesh does not have much effect on the reactor performance in terms of reduction equivalent dose (RED). The numerical results agree well with the experimental measurements, hence validating the numerical model. With this achieved, the numerical model is applied to study other scaled reactors: LP12, LP40, LP60 and LP80. Comparisons show that LP40 has the highest RED and log inactivation among all the reactors while LP80 has the lowest RED and log inactivation.

Effects of onion extracts on growth performance, carcass characteristics and blood profiles of white mini broilers.

This experiment was carried out to investigate effects of onion extract on growth performance, meat quality and blood profiles of White mini broilers. Total of 600 one-d-old male White mini broiler chicks were divided into four groups and fed control diets (non-medicated commercial diet or antibiotics medicated) or experimental diets (non-medicated diets containing 0.3% or 0.5% onion extract) for 5 wks. The final body weight (BW) and weight gain of the group fed non-medicated control diet were lower than those of medicated control group (p<0.01). The chicks fed diet with 0.3% or 0.5% onion extract showed a similar BW to that of medicated control group. The relative weight of various organs, such as liver, spleen, bursa of Fabricius, abdominal fat, and the activities of serum enzymes were not affected by dietary treatments. There were no significant differences in meat color among groups. Whereas, groups fed diets containing onion extract had slightly lower cooking loss and higher shear force value, but not significantly. The concentrations of serum free cholesterol and triacylglycerol in groups fed diet containing onion extract were significantly decreased compared with those of controls (p<0.01). In conclusion, the onion extracts exerted a growth-promoting effect when added in White mini broiler diets, reflecting potential alternative substances to replace antibiotics.

Effects of Dietary Fermented Chlorella vulgaris (CBT(®)) on Growth Performance, Relative Organ Weights, Cecal Microflora, Tibia Bone Characteristics, and Meat Qualities in Pekin Ducks.

Fermented Chlorella vulgaris was examined for its effects on growth performance, cecal microflora, tibia bone strength, and meat qualities in commercial Pekin ducks. A total of three hundred, day-old male Pekin ducks were divided into three groups with five replicates (n = 20 ducklings per replicate) and offered diets supplemented with commercial fermented C. vulgaris (CBT(®)) at the level of 0, 1,000 or 2,000 mg/kg, respectively for 6 wks. The final body weight was linearly (p = 0.001) increased as the addition of fermented C. vulgaris into diets increased. Similarly, dietary C. vulgaris linearly increased body weight gain (p = 0.001) and feed intake (p = 0.001) especially at the later days of the feeding trial. However, there was no C. vulgaris effect on feed efficiency. Relative weights of liver were significantly lowered by dietary fermented C. vulgaris (linear effect at p = 0.044). Dietary fermented C. vulgaris did not affect total microbes, lactic acid bacteria, and coliforms in cecal contents. Finally, meat quality parameters such as meat color (i.e., yellowness), shear force, pH, or water holding capacity were altered by adding fermented C. vulgaris into the diet. In our knowledge, this is the first report to show that dietary fermented C. vulgaris enhanced meat qualities of duck meats. In conclusion, our study indicates that dietary fermented C. vulgaris exerted benefits on productivity and can be employed as a novel, nutrition-based strategy to produce value-added duck meats.

Evaluation of dietary multiple enzyme preparation (natuzyme) in laying hens.

The current experiment was designed to evaluate the efficacy of adding the multi-enzyme mixture (Natuzyme) into layers' diets with different levels of energy and available phosphorus in relation to laying performance, egg qualities, blood cholesterol level, microflora and intestinal viscosity. Two hundred and fifty 43-wk-old Hy-Line commercial layers were divided into five groups with five replicates per group (10 birds per replicate) and fed one of five experimental diets. A corn and soybean meal-based control diet was formulated and used as a control diet. Two experimental control diets were formulated to reduce energy and crude protein contents (rE) or energy, crude protein and phosphorus contents (rEP). In addition, Natuzyme was added into either rE (rE-Natu500) or rEP (rEP-Natu500) diet to reach a concentration of 500 mg per kg of diet. The experiment lasted 8 weeks. There were no significant differences in feed intake, egg production, egg weight, egg qualities such as eggshell color or Haugh unit, total cholesterol, relative organ weights and cecal microflora profiles between any dietary treatments. Natu500 supplementation into the rE diet, but not rEP diet significantly increased egg mass and eggshell qualities such as strength and thickness, but it decreased cecal ammonia concentration and intestinal viscosity in laying hens. In conclusion, the present study shows that adding multiple enzyme preparation could improve performance of laying hens fed energy and protein restricted diets.

Comparison of growth performance, carcass characteristics and meat quality of korean local chickens and silky fowl.

This study was conducted to compare growth performance, carcass characteristics and meat quality of 4 breeds of local chicken. A total of 480 1-d-old chicks were distributed to 16 pens, with 4 treatments of breed, 4 replicates and 30 chicks per pen. Three Korean local breeds of white-mini broiler, Hanhyup-3-ho, and Woorimatdag, and a breed of silky fowl were raised under identical rearing and feeding conditions for 31-d, 37-d, 36-d, and 59-d, respectively. The BW and feed consumption on a pen basis were weekly measured for all pens, and ADFI, ADG and gain:feed were calculated for each pen. The ADFI and ADG of 3 breeds of Korean local chicken were greater than those of silky fowl (p<0.05). Within the Korean local breeds, ADFI of white-mini broiler was the highest (p<0.05), and ADG of Hanhyup-3-ho and white-mini broiler was the highest (p<0.05). Gain:feed of silky fowl was less than that of the 3 breeds of Korean local chicken. The carcass and breast yield of white-mini broiler were the greater than those of other breeds (p<0.05). The breast meat color (CIE L*, a*, and b*) of 3 breeds of Korean local chicken were higher than that of silky fowl (p<0.05). The breast meat of Hanhyup-3-ho had greater cooking loss (p<0.05), whereas water holding capacity and pH were less than those of other breeds (p<0.05). The color score of 3 breeds of Korean local chicken was higher than that of silky fowl (p<0.05). Woorimatdag had a higher score on tenderness (p<0.05), whereas flavor score was less than that of other breeds (p<0.05). In conclusion, 4 local breeds of chicken have some unique features and seem to have more advantages, and this information can help consumers who prefer healthy and premium chicken meat.

Carcass Characteristics and Meat Quality of Korean Native Ducks and Commercial Meat-type Ducks Raised under Same Feeding and Rearing Conditions.

This study was conducted to compare carcass characteristics and physico-chemical meat quality in two different genotype ducks raised under identical feeding and rearing conditions. A total of ninety 1-d-old Korean native ducks (KND, n = 45) and commercial meat-type ducks (Grimaud, n = 45) were fed same experimental diets during 56 d and 42 d, respectively to obtain similar slaughter weights. The experimental diet for starter period contained 20% crude protein (CP) and 2,900 kcal nitrogen corrected true metabolizable energy (TMEn)/kg of diet and that for grower period contained 17% CP and 3,050 TMEn/kg of diet. Average daily gain and feed efficiency of KND were inferior to those of commercial meat-type ducks (p<0.05). Carcass weight was not different between two genetically different ducks, but carcass yield of KND was significantly higher (p<0.05) than that of commercial meat-type ducks. There were no significant differences in cooking loss and pH of breast meat between two genetically different ducks, but water holding capacity of KND was significantly higher than that of commercial meat-type ducks. The linoleic acid and total polyunsaturated fatty acid of breast meat from KND were significantly higher (p<0.05) than the corresponding part from commercial meat-type ducks. Significant differences were detected in water holding capacity and the content of linoleic acid and polyunsaturated fatty acid, which were significantly higher in KND, whereas growth performance tended to be superior in commercial ducks. At the market weight, the meat from KND was judged to have better qualities with regard to higher water holding capacity and greater content of polyunsaturated fatty acid compare with meat from commercial meat-type duck.

Growth performance and carcass characteristics of korean native ducks fed diets with varying levels of limiting amino acids.

There are multiple experiments conducted with male Korean native ducks (KND) to evaluate the optimal levels of limiting amino acids (AA). In Exp. 1, a total of 450 one-d-old male KNDs were divided into five groups with six replicates and fed experimental diets with varying levels of lysine, total sulfur amino acids (TSAA) and threonine (T1, 0.90/0.74/0.70%; T2, 1.00/0.82/0.77%; T3, 1.10/0.90/0.85%; T4, 1.20/0.98/0.93%; T5, 1.30/1.07/1.01%) to 21 d of age. In Exp. 2, one-d-old male KND were received and fed commercial starter diet from hatching to 21 d of age, and then divided into five groups with six replicates and fed one of five diets varying levels of lysine, TSAA, and threonine (T1, 0.73/0.62/0.54%; T2, 0.80/0.68/0.60%; T3, 0.87/0.74/0.65%; T4, 0.94/0.80/0.70%; T5, 1.01/0.86/0.75%) during 22 to 56 d of age, respectively. The BW gain was linearly increased as dietary limiting AA levels increased to 1.20% lysine, 0.98% TSAA and 0.93% threonine. There were no significant differences in feed intake, gain:feed and uniformity among groups. In Exp. 2, the BW gain and gain:feed were not affected by dietary limiting AA levels. There were no significant differences in carcass characteristics and meat quality among groups. The growth performance and carcass characteristics did not show the significant response to increasing dietary limiting AA levels in KND during 22 to 56 d of age. In conclusion, the levels of lysine, TSAA and threonine necessary to maximize growth for starter phase were at least 1.20%, 0.98%, and 0.93%, respectively. On the other hands, KND require relatively low levels of limiting AA for late growth and carcass yield. The dietary levels of 0.73% lysine, 0.62% TSAA and 0.54% threonine appear to be adequate during growing phase.

Effects of dietary persimmon peel and its ethanol extract on the production performance and liver lipids in the late stage of egg production in laying hens.

The purpose of this study was to investigate the dietary effects of persimmon peel (PP) and PP ethanol extract (PPE) on egg production, egg quality, and liver lipids in the late stage of egg production in laying hens. One hundred and twenty 50-wk-old Hy-Line Brown layers (n = 120) were fed different diets. Four replicate groups of 6 hens each were randomly assigned to 5 dietary treatments. The 5 dietary treatments were as follows: i) CON, basal diet; ii) PP 0.15, CON+0.15% PP (0.035% tannin); iii) PP 0.5, CON +0.5% PP (0.117% tannin); iv) PPE 0.075, CON+0.075% PPE (0.03% tannin); and v) PPE 0.25, CON+0.25% PPE (0.11% tannin). The total tannin concentration of PPE was higher (p<0.05) than that of PP. Egg production in the PP 0.5 group was higher than in the other groups. Egg production and mass of hens in the PPE 0.25 group showed a greater decrease than that in the other groups (p<0.05). Eggshell color in the PP 0.15, PP 0.5, and PPE 0.075 groups was lighter than that of the control group (p<0.05). The Haugh unit for the groups that were fed PP and PPE were significantly higher than that in the other groups after 7 d of storage (p<0.05). Therefore, PP seems an effective feed additive for improving the production performance and egg quality in late stage laying hens.

The Dietary Effects of Fermented Chlorella vulgaris (CBT(®)) on Production Performance, Liver Lipids and Intestinal Microflora in Laying Hens.

Fermented Chlorella vulgaris CBT(®) was evaluated for its effects on egg production, egg quality, liver lipids and intestinal microflora in laying hens. One hundred and eight Hy-line Brown layers (n = 108), 80 wk of age, were fed a basal diet supplemented with CBT(®) at the level of 0, 1,000 or 2,000 mg/kg, respectively for 42 d. Egg production was measured daily and egg quality was measured every two weeks. Five eggs from each replicate were collected randomly to determine egg quality. Egg production increased linearly with increasing levels of CBT(®) supplementation (p<0.05), although there was no significant effect of treatment on feed intake. Egg yolk color (p<0.001) and Haugh unit (p<0.01) improved linearly with increasing dietary CBT(®). Hepatic triacylglycerol level was linearly decreased with increasing dietary CBT(®) (p<0.05). The supplemental CBT(®) resulted in linear (p<0.001) and quadratic (p<0.01) response in population of cecal lactic acid bacteria. In conclusion, fermented Chlorella vulgaris supplemented to laying hen diets improved egg production, egg yolk color, Haugh unit and positively affected the contents of hepatic triacylglycerol and the profiles of cecal microflora.

Nutritional and Hormonal Induction of Fatty Liver Syndrome and Effects of Dietary Lipotropic Factors in Egg-type Male Chicks.

This experiment was conducted with male chicks to investigate the influence of hormones and nutrients on the development of fatty liver syndrome (FLS) as well as the effects of dietary lipotropic factors on hepatic fat accumulation and lipogenic enzyme gene expression. A total of two-hundred sixteen 4-wk-old Hy-Line male chicks were divided into six groups and fed an experimental diet (T1, low-energy diet with low levels of lipotropic factors; T2, high-energy diet with low levels of lipotropic factors; T3 and T5, low-energy diet with high levels of lipotropic factors; T4 and T6, high-energy diet with high levels of lipotropic factors) for six weeks. The chicks in T5 and T6 groups were treated with intramuscular injections of estradiol benzoate for three days prior to biopsy and clinical analysis of FLS. Chicks treated with estrogen had significantly greater liver weights than untreated chicks. The abdominal fat contents were increased in chicks consuming high-energy diets as compared to those consuming low-energy diets. Treatment with estrogen significantly increased the concentrations of serum cholesterol, triacylglycerol and phospholipid (p<0.05). The hepatic triacylglycerol levels were tenfold higher in the estrogen treated chicks than in the untreated chicks. There were no significant differences in malondialdehyde levels between the treatment groups. Estrogen treatment dramatically increased the levels of fatty acid synthetase, acetyl-CoA carboxylase and ApoB mRNA. The results indicated that treatment with exogenous estrogen in growing male chicks induced hepatic fat accumulation, which might be partially due to increased lipogenic enzyme gene expression.

Changes in hepatic lipid parameters and hepatic messenger ribonucleic acid expression following estradiol administration in laying hens (Gallus domesticus).

Fatty liver hemorrhagic syndrome (FLHS) is characterized by increased hepatic triacylglycerol content associated with liver hemorrhages and results in a sudden decline in egg production. Genetic, environmental, nutritional, and hormonal factors have all been implicated in the etiology of FLHS, but the exact cause of FLHS is still unknown. Estrogens have been implicated in the development of excess fat content of the liver and in the etiology of FLHS. This study investigated estradiol (E(2)) administration in hens and its effect on lipid metabolism. Hy-Line Brown laying hens were intramuscularly injected with E(2) on a daily basis for 3 wk. The dosages were 0, 0.5, and 1.0 mg/kg of BW, with corn oil injections used as a control. Egg production and quality were measured among the groups, with no significant difference seen in egg production. Liver weights of hens treated with E(2) were greater than those of control hens, but the increase was not statistically significant. Serum glutamic-oxaloacetic transaminase and glutamic-pyruvic transaminase activities and E(2) plasma concentrations increased in a dose-dependent manner, with plasma concentration of E(2) increasing from 6,900 to 19,000 pg/mL. No significant differences in free cholesterol or phospholipids were observed, but there was a significant increase in hepatic triacylglycerol levels. Injection with E(2) showed an increased expression of mRNA for peroxisome proliferator-activated receptor γ (23-fold), but not for peroxisome proliferator-activated receptor α. A statistically significant increase was seen for fatty acid synthase, apolipoprotein B, and adenosine triphosphate citrate lyase, but not for acetyl coenzyme A carboxylase, apolipoprotein VLDL-II, microsomal triglyceride transport protein, or malic enzyme. For proteins involved in the oxidation of E(2), only cytochrome P450 3A37 showed a statistically significant increase. The present results suggest that E(2) upregulates the synthesis of fatty acids and triacylglycerols and the accumulation of hepatic lipids by increasing mRNA expression related to lipid metabolism, and that excess E(2) in the blood leads to activation of E(2) catabolic metabolism (cytochrome P450 3A37)-related mRNA expression.

Characteristics of growth and protein synthesis in skeletal muscles of normal and dystrophic chickens.

Several characteristics of cellular growth and protein synthesis were measured in vivo in the breast and leg muscles of normal (line 454) and hereditary muscular dystrophic (line 455) New Hampshire chickens at different ages. Fractional rates of protein synthesis (ks) were calculated from the rate of incorporation of labeled tyrosine administered continuously via a subcutaneous injection of an emulsion of L-[U-14C]tyrosine in sesame oil. Only the breast muscle showed signs of gross hypertrophy. The hypertrophy involved an abnormally rapid accumulation of protein, DNA and RNA. In dystrophic chickens, ks was at least 170% of the normal rates at 2, 5 and 52 weeks. The elevated ks was presumably a reflection of the higher DNA and RNA concentrations relative to those in normal birds. Because the RNA/DNA ratio and the activities of RNA and DNA were similar to values observed in normal birds, there may be no defect in the synthesis machinery per se.

Structure of ribosome-bound messenger RNA as revealed by enzymatic accessibility studies.

Digestion with ribonuclease T2 has been used to study the size of poly(U) protected by ribosome binding. Several different preparations of ribosomes all appear to cover 49 nucleotides of message; however, there are two partially accessible internal nuclease cleavage sites, which yield, ultimately, fragments 20, 16 and 13 nucleotides in length. Curiously, the site between fragments of length 20 and 16 is accessible to RNase T2 but not to the several much smaller RNases. Arguments based on the quantitative pattern of cleavage and comparisons with previous studies lead to the conclusion that the 20-mer is the 5' fragment, while 13-mer (which is lost the moment it is cleaved from the 16-mer) is the 3' fragment. Both ribosome-bound tRNAs appear to contact only the 16-mer. The presence of the two internal cleavage sites fits nicely with recent electron microscopic data suggesting that mRNA forms a loop around the 30 S subunit.

Effect of the level of dietary protein on the utilization of alpha-ketoisocaproate for protein synthesis.

The efficiency of alpha-ketoisocaproate (KIC) as a dietary substitute for leucine in rats on varying protein intake was estimated by an isotopic method, previously shown to yield the same results as comparative growth experiments. 14C-KIC and 3H-leucine are injected orally. Six hours later the ratio, R, of 14C/3H in isolated proteins, divided by the same ratio in the injectate is measured. This ratio has been shown to be approximately equal to nutritional efficiency of KIC relative to leucine. As dietary protein increased from 6.3% to 48.3%, whole body protein R decreased from 0.515 +/- 0.045 to 0.299 +/- 0.016. Variations with protein intake were noted in R of protein isolated from individual organs. The magnitude of R in these organs varied two-fold, in the following sequence: brain greater than heart greater than or equal to skeletal muscle greater than or equal to salivary gland greater than or equal to kidney greater than liver. Whole body protein R could be confidently predicted (r2 = 0.992) from R in the protein of kidney and muscle. Thus the nutritional efficiency of KIC as a dietary substitute for leucine in individual organs as well as in the whole animal is strongly dependent on the level of protein intake.

Expression of the insulin-like growth factors (IGFs) and the IGF-binding proteins (IGFBPs) in human gastric cancer cells.

Insulin-like growth factor (IGF)-I and -II are potent mitogens and postulated to exert autocrine, and paracrine effects on growth regulation in human gastric cancer. Their mitogenic effects are tightly regulated by the IGF binding proteins (IGFBPs). In this study, we evaluated the mRNA expression of IGF-I, IGF-II and the IGFBPs in a panel of human gastric cancer cell lines, and normal and tumour tissue specimens from patients with gastric cancer by reverse transcriptase-polymerase chain reaction (RT-PCR) and competitive PCR. Conditioned media (CM) of the gastric cancer cell lines were studied for the secretion of the IGFBPs by western ligand blot (WLB) and western immunoblot (WIB). IGF-I and IGF-II were expressed in all of the gastric cancer cell lines, and the normal and tumour tissue specimens. Overexpression of the IGFs, in particular, IGF-II, was observed in the tumour tissues. The expression pattern of IGFBPs was heterogeneous among the gastric cancer cell lines. IGFBP-2 was expressed in all of the gastric cancer cell lines, whereas IGFBP-1 was not detected in any cell lines. IGFBP-4 was expressed in the most of cell lines. IGFBP-3, IGFBP-5 and IGFBP-6 were expressed in approximately 50% of cell lines. In addition, exogenous IGF-I and IGF-II stimulated the proliferation of gastric cancer cells, suggesting the existence of a functional IGF system in gastric cancer. Taken together, our data-suggest that the IGF-IGFBP system may play an important role in the initiation, progression and metastasis of gastric cancer. Further studies are needed to understand the exact role of IGFs and IGFBPs in gastric neoplasia.

Modulation of neuroendocrinological function by psychosomatic training: acute effect of ChunDoSunBup Qi-training on growth hormone, insulin-like growth factor (IGF)-I, and insulin-like growth factor binding protein (IGFBP)-3 in men.

The neuroendocrine system is regarded as the major link between the psychological state and the immune system in man. The present study was undertaken to examine the acute effect of ChunDoSunBup Qi-training, a traditional psychosomatic training, on the plasma level of growth hormone (GH), insulin-like growth factor (IGF)-I and insulin like growth factor binding protein (IGFBP)-3 in young men. To characterize the plasma level of hormones and the pattern of IGFBP-3 at pre- (-10 min), mid-time (40 min), and immediately after (post-time, +10 min) Qi-training, radioimmunoassay (RIA) and western ligand blot (WLB) analysis were used. The plasma level of GH at the mid-time was significantly increased (P<0.05) compared to the level at pre-time of Qi-training. The plasma level of IGF-I was also increased at mid-time (P<0.05) and immediately after Qi-training. There was a significant correlation between the levels of GH and IGF-I immediately after Qi-training (r=0.69, P<0.01). In this study, the change of IGFBP-3 among the several IGFBPs was determined. There was a relative shift in IGFBP-3 for the 43-kDa fraction during mid-time of Qi-training (P<0.05). These results suggest that Qi-training influences the growth hormone, IGF-I and IGFBP-3 status via brain-target organ axis in men.

Identification of immunoreactive atrial natriuretic peptide in the gallbladder and bile juice of rabbit, pig and human.

The presence of immunoreactive atrial natriuretic peptide (irANP) in rabbit, pig and human gallbladders was investigated using radioimmunoassay and immunohistochemistry. Serial dilution curves of gallbladder tissue and bile juice extracts were paralleled to the standard curve of atriopeptin III. Gel filtration profiles of gallbladder tissue extracts showed a major peak corresponding to rat pro-ANP. The amounts of irANP in rabbit, pig and human gallbladders were 30.0 +/- 12.3 pg/mg (n = 7), 7.0 +/- 2.0 fg/mg (n = 7) and 17.7 +/- 2.0 fg/mg wet tissue (n = 8), respectively. Bile juice was also shown to contain irANP but with small molecular mass. The amounts of irANP in the rabbit, pig and human bile juice were 25.0 +/- 2.0 (n = 7) and 0.50 +/- 0.02 (n = 7), and 1.3 +/- 0.1 pg/ml (n = 8), respectively. The immunohistochemical staining of the rabbit gallbladder tissue revealed the presence of irANP in the luminal epithelium and smooth muscle layer. The amount of irANP was higher in the luminal epithelium than in the rest of the gallbladder tissue from rabbits (0.30 +/- 0.06 vs. 0.01 +/- 0.01 pg/microgram protein, P < 0.01). These findings suggest that ANP may be synthesized and stored in the gallbladder, and may have a role in the regulation of fluid balance and cystic motility.

L-Carnitine changes the levels of insulin-like growth factors (IGFs) and IGF binding proteins in streptozotocin-induced diabetic rat.

This study investigated the effects of L-carnitine on insulin-like growth factor-I/II (IGF-I/II) and insulin-like growth factor binding proteins (IGFBPs) in streptozotocin (STZ)-induced diabetic rats. Each rat in the three L-carnitine-treated groups was injected subcutaneously with L-carnitine, 50 (D50), 100 (D100), or 200 (D200) mg/kg body weight every other day for four weeks, and animals in normal (N) and diabetic (DM) groups received saline by the same method. Diabetic rats had significantly lower carnitine concentrations in serum and liver compared with normal rats. Total carnitine concentrations were increased dose-dependently by carnitine treatment. Total IGF-I in serum from diabetic rats was increased dose-dependently by carnitine treatment, but was statistically significant only in the D200 group. The expression of liver IGF-I mRNA was lower in diabetic rats than in normal rats and increased by L-carnitine treatment. L-Carnitine treatment of diabetic rats had no effect on the levels of IGF-II in serum, liver, and kidney. Although the levels of IGF-II in serum and kidney of diabetic rats were increased in comparison with normal rats, IGF-II mRNA was not expressed in liver. Diabetic rats had markedly lower IGFBP-3 than normal rats did, and IGFBP-3 was increased by L-carnitine treatment. These results demonstrate that L-carnitine treatment of diabetic rats modulates the IGFs/IGFBPs axis. Especially note-worthy is that L-carnitine at a dose of 200 mg/kg/48 h for four weeks was able to restore serum total IGF-I in STZ-induced diabetic rats to nearly normal levels.

Growth and protein turnover in the skeletal muscles of broiler chicks.

Growth and protein turnover were examined in the breast (pectoralis thoracica) and the leg (gastrocnemius-peroneus) muscles of broiler chicks at 1, 2, 4, and 6 weeks posthatching. The fractional rate of protein synthesis (ks) was measured by an isotope emulsion method. The fractional degradation rate (kd) was calculated from the difference in ks and fractional deposition rate (kg), which was estimated from regression equations of muscle size and protein content on body weights. The growth rate (%/day) of skeletal muscle exceeded that of the whole body. Muscle growth involved an increase in the total deoxyribonucleic acid (DNA) and the DNA-unit size and a subsequent decrease in the concentrations of nucleic acids without alteration in the ribonucleic acid (RNA):DNA ratio and RNA and DNA activity. The ks in breast muscle protein fell markedly from 48 to 16%/day between 1 and 6 weeks posthatching, whereas in leg muscle, ks underwent a more gradual decrease; from 36 to 17%/day during the same period. These changes resulted mainly from the reduction of DNA and RNA concentrations with age. The kd decreased only slightly between 1 and 2 weeks in the both muscle groups. The kg also showed a developmental fall from 33 to 4%/day and from 21 to 4%/day in the breast and leg muscles, respectively, during the 5-week period.(ABSTRACT TRUNCATED AT 250 WORDS)

Characteristics of growth and protein turnover in skeletal muscle of turkey poults.

Protein turnover and DNA and RNA levels were measured in the breast (pectoralis thoracica) and leg (gastrocnemius-peroneus) muscles of large white (Nicholas strain) turkey poults from 1 to 8 weeks of age to investigate their cellular growth and to evaluate the influence of protein turnover on muscle growth. Fractional rates of protein deposition (kg) were determined from regression equations of muscle size and protein content on body weights. Protein synthesis rates (ks) were measured by an isotope emulsion technique. Protein degradation rates (kd) were estimated by the difference between ks and kg. Muscle growth involved increases in total deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), an increase in the DNA-unit size, and decreases in concentrations of the nucleic acids without changes in the RNA:DNA ratio or RNA and DNA activity. The muscles showed developmental changes in ks from 56 to 10%/day and from 38 to 13%/day in breast and leg, respectively, over the 7-week period. The fractional degradation rate also fell from 22 to 7%/day in the breast muscle and from 21 to 10%/day in the leg muscle. The disproportionate decline of ks and kd resulted in an age-associated fall in kg from 34 to 4%/day and from 18 to 3%/day in the breast and the leg muscles, respectively. The efficiency of protein deposition decreased from 61 to 35% in breast muscle and 46 to 20% in leg muscle. The results were qualitatively similar to those obtained in a study with broiler chicks.