• Animal Bioscience
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• v.37 no.12
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• pp.2113-2125
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• 2024

Objective: The present study aimed to investigate the effectiveness of dietary β-mannanase supplementation on growth performance, intestinal morphology, digesta viscosity, and dietary nutrient utilization in broiler chickens through a meta-analysis. The effects were further examined by a meta-regression analysis with activity levels of β-mannanase in broiler diets. Methods: A total of 23 studies, which were conducted in 11 countries and completed between December 2003 and August 2023, were selected for this meta-analysis. The standardized mean difference and its 95% confidence interval were calculated as the effect size metrics using random effect model, with I² value being utilized to measure heterogeneity. Investigated measurements included body weight gain (BWG), feed intake, feed conversion ratio (FCR), villus height (VH), crypt depth (CD), VH:CD ratio, digesta viscosity, nitrogen-corrected metabolizable energy (AME_n), apparent ileal digestibility (AID), and apparent total tract retention (ATTR) of dry matter (DM), gross energy (GE), and nitrogen (N). All statistical analyses were performed using R version 4.3.3. Results: Results revealed significant positive effects of dietary β-mannanase supplementation on BWG (p = 0.005), FCR (p<0.001), VH (p<0.001), VH:CD (p<0.001), digesta viscosity (p<0.001), AME_n (p = 0.011), AID of GE (p = 0.002) and N (p = 0.003), and ATTR of DM (p = 0.019), GE (p = 0.002), and N (p = 0.005) in broiler chickens. In the meta-regression analysis, increasing activity levels of β-mannanase in broiler diets increased VH:CD (p< 0.001; R² = 79.2%) and AID of N (p = 0.038; R² = 67.4%). Conclusion: The current meta-analysis indicates that dietary β-mannanase supplementation improves energy and nutrient utilization in broiler diets possibly by decreasing digesta viscosity and enhancing intestinal morphology in broiler chickens. These beneficial effects can contribute to improved growth performance in broiler chickens.

• Journal of Animal Science and Technology
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• v.45 no.6
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• pp.957-966
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• 2003

Effects of Salmonella typhimurium lipopolysacharide(LPS) and dietary krill meal on the Growth and feed utilization were investigated in broiler chicks. Eight cages of five newly hatched chicks each were assigned and fed to one of the experimental diets containing 0.0,(basal) 0.5 or 1.0% krill meal during 3 weeks of experimental period. And half(four) of the eight cages were i.p. injected with saline or LPS(Immune response activation) every alternate day three times beginning 8 day-old during 2 week of age. Dietary krill meal did not affect growth, feed efficiency, nitrogen balance(NB), uric acid excretion, and ME utilization when the saline was injected. However, the immune response activation lowered daily gain and feed intake and NB and increased uric acid excretion, and the relative liver and spleen weight. Also, birds fed diet containing krill meal 1.0% reduced the feed efficiency and increased spleen weight, and ME and NB or ME required for gain compared with those fed basal and krill meal 0.5% diets in LPS-injected chicks. During recovery period from the immunological stress in 3rd week of age, the krill meal diet reduced the weight of liver and spleen, The results showcd that dietary krill meal did not affect the growth of broiler chicks, but the higher uric acid excretion or dietary ME value indicated the increased protein decomposition or absorption of dietary energy sources in immune response activated birds.

• Journal of Nutrition and Health
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• v.55 no.1
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• pp.10-20
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• 2022

This article evaluated levels of Estimated Average Requirements (EARs), Reference Nutrient Intakes (RNIs), and Acceptable Macronutrient Distribution Ranges (AMDRs) of protein using the recently revised Dietary Reference Intakes (DRIs) for Koreans (2020). Dietary protein requirements are based on amounts sufficient to satisfy physiological demands to accomplish nitrogen equilibrium. The same principle was applied to estimate EARs and RNIs, for adults in DRIs conducted in 2015 and 2020 in Koreans. EAR was estimated to be 0.73 g/kg body weight/day, according to data (0.66 g/kg body weight/day) obtained using the nitrogen balance method and adjusted by efficiency of protein use (90%). RNI was calculated as EAR increased by an amount equal to twice the standard deviation of an age group so as to cover 97.5% of the group and was found to be 0.91 g/kg body weight/day. For weaned infants, children, and adolescents, growth requirement was added to estimate EAR. In particular, growth requirement was adjusted by efficiency of protein use in the revised EAR, which led to higher EARs for weaned infants, children, and adolescents of both genders as compared with 2015 DRIs. The AMDR for protein was set at 7%-20% of energy intake, which was the same as 2015 DRIs. Current, average protein intake by the Korean population is almost twice times the EAR, which suggests it might be better to increase the minimal margin for AMDR. However, it was not adjusted in this revision due to lack of evidence.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.5
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• pp.660-665
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• 2017

Objective: The objective of the study was to determine the effects of increasing levels of metabolizable protein (MP) on lactation performance and nitrogen (N) efficiencies in lactating dairy cows. Methods: Nine multiparous cows in mid lactation [$113{\pm}25$ days in milk] received three treatments in a $3{\times}3$ Latin square design with a period length of 21 days. The treatments were three diets, designed to provide similar energy and increasing supply of MP (g/d) (2,371 [low], 2,561 [medium], and 2,711 [high] with corresponding crude protein levels [%]) 15.2, 18.4, and 20.9, respectively. Results: Increasing MP supplies did not modify dry matter intake, however, it increased milk protein, fat, and lactose yield linearly. Similarly, fat corrected milk increased linearly (9.3%) due to an increase in both milk yield (5.2%) and milk fat content (7.8%). No effects were observed on milk protein and lactose contents across the treatments. Milk nitrogen efficiency (MNE) decreased from 0.26 to 0.20; whereas, the metabolic efficiency of MP decreased from 0.70 to 0.60 in low to high MP supplies, respectively. The concentration of blood urea nitrogen (BUN) increased linearly in response to increasing MP supplies. Conclusion: Increasing MP supplies resulted in increased milk protein yield; however, a higher BUN and low MNE indicated an efficient utilization of dietary protein at low MP supplies.

• Journal of Nutrition and Health
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• v.27 no.7
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• pp.699-708
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• 1994

This study aimed to verify the nutritional and curative effects of protein hydrolysate in rats with cysteamine-induced duodenal uncer. Duodenal ulcer rat model was established by intraperitoneal injections of cysteamine. Sprague-Dawley, female rats weighing approximately 200g were intraperitoneally injected twice cysteamine(13mg/100g BW) at intervals of 3h per day. This procedure was repeated 3$\times$at intervals of 3d. Animals fed on 10% casein diet for infection periods. After last injection, 4 kinds of diets(10% casein, 20% casein, 10% casein hydrolysate, 20% casein hydrolysate) were given. Gastric montility, trypsin activity in gastrointestinal content, retention rate of nitrogen, plasma total protein, albumin, amino-N, urinary urea nitrogen, creatinine and hydroxyproline were analyzed for nutritional effects of dietary nitrogen levels(10%, 20%) and sources(casein, casein hydrolysate). In duodenal ulcer rat model, there was no differences between 20% casein diet and 20% casein hydrolysate in the view of severeness of ulcer, gastric emptying rate, serum total protein, serum albumin, plasma $\alpha$-amino-N, UUN, creatinine excretion, GFR, nitrogen retention. On the other hand, rats on 10% casein hydrolysate diet group had more curative effect of the ulcer, higher plasma albumin concentration and nitrogen retention than 10% casein diet group. The casein hydrolysate diet group was lower trypsin activity in small intestinal content than the casein diet group, at both nitrogen levels(10%, 20%). The results suggest that protein hydrolysate be applied in diet therapy for the patients with gastrointestinal ulcer.

• Asian-Australasian Journal of Animal Sciences
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• v.5 no.4
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• pp.741-746
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• 1992

The effects of 5%, 10%, 15% and 20% dietary cellulose levels on the nutrient utilization in chickens were investigated. Four experimental diets were alternatively given to 8 colostomized White Leghorn cockerels to make a $4{\times}4$ Latin-square design. The diets of 70 g.day were force-fed once a day, and water was given freely. The digestibilities of DM and energy increased linearly with the increase in dietary cellulose level. The digestibilities of ether extract and nitrogen-free extract were not so much influenced by the dietary cellulose level. The digestibility of acid detergent fiber was very low and not influenced by the dietary cellulose level. The digestibility of neutral detergent fiber was not different among the diets containing 5%-15% cellulose, but that of the 20% cellulose diet was diminished. This might be due to the reduction of hemicellulose digestibility. True digestibility and biological value of protein were also not influenced by the dietary cellulose level from 5% to 20%. In conclusion, no ill-effect was found even when the chicken was fed a diet containing 20% of cellulose.

• Asian-Australasian Journal of Animal Sciences
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• v.7 no.2
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• pp.207-212
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• 1994

Effects of dietary cellulose and protein levels on nutrient utilization in chickens were investigated. Four experimental diets containing 5% (low cellulose) or 20% (high cellulose) cellulose in combination with 10% (low protein) or 20% (high protein) protein of 70 g/day were alternatively forced-fed to eight colostomized White Leghorn cockerels once a day to make $4{\times}4$ Latin-square design. The digestibilities of DM and energy decreased with the increase in cellulose level, but not affected by dietary protein level. Ether extract digestibility was higher in the high cellulose diets than in the low cellulose protein level. Ether extract digestibility was higher in the high cellulose diets than in the low cellulose diets. The digestibility of nitrogen free extract had the same trend with the digestibility of DM and energy. The digestibility of acid detergent fiber was not so much different among the diets, but the NDF digestibility was lower in the high cellulose diets than in the low cellulose diets, due to the low hemicellulose digestibility. The true digestibility of protein was influenced by both of the dietary protein and cellulose levels, and their interaction was found. The dietary protein level affected the biological value of protein but the dietary cellulose level did not, and consequently the biological value of protein in the low protein diets was lower than in the high protein diets.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.12
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• pp.1732-1737
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• 2002

This study was conducted to examine the effect of Leucaena leucocephala-Morus alba-Azadirachta indica (2:1:1) based leaf meal mixture as nitrogen source to partially replace (50%) soybean meal in conventional supplements on the performance of goats. Twelve non-descript female goats were divided into two equal groups in a completely randomized design to receive either the leaf meal mixture based supplement (LMAM) or soybean meal incorporated concentrate (SBM) and wheat straw for ad libitum intake for a two month period. The goats given LMAM and SBM concentrate had similar dry matter intake ($50.2{\pm}1.67g/kg\;W^{0.75}$) and nutrient digestibility. Nitrogen intake and its faecal and urinary excretion were similar irrespective of diets. The balance of nitrogen was positive and comparable ($1.63{\pm}0.08g/d$) in both dietary treatments. The plane of nutrition on both diets was comparable and the digestible crude protein and total digestible nutrients values of the composite diets offered did not differ significantly between the dietary supplements. The serum concentration of enzymes alanine aminotransferase and aspartate aminotransferase were statistically similar in both the groups, while haemoglobin and serum urea levels were significantly (p<0.05) higher in LMAM and SBM treatments, respectively. It was concluded that the leaf meal mixture of Leucaena leucocephala-Morus alba-Azadirachta indica could be used as a vegetable protein supplement to wheat straw based diet of goats.

• Asian-Australasian Journal of Animal Sciences
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• v.26 no.12
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• pp.1726-1731
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• 2013

The effects of different dietary electrolyte balance (DEB) on growth performance, nitrogen (N) metabolism and some blood biochemical parameters were investigated in 2 to 3 months old growing rabbits. A total of 150 growing rabbits of 2 months age were randomly divided into five groups according to average body weight, with 30 rabbits in each group. The DEB levels of the five experimental diets were -154, -3.16, +201, +347, and +500 meq/kg of dry matter (DM), respectively. There was a 7-d adaptation period and a 23-d experimental period. The results showed that the DEB levels had a quadratic affect on the average daily feed intake (ADFI) (p<0.001). The greatest ADFI was achieved when the DEB level was +201 meq/kg DM. Fecal N (FN) content linearly decreased (0.047), while digestible N (DN), retained N (RN), efficiency of intake N converted into digestible N (DN/IN) and the efficiency of intake N converted into retained N (RN/IN) linearly increased with the DEB increase (0.020, 0.004, 0.021, and 0.049, respectively). Serum phosphorus (P) ion content linearly increased with the DEB increase (p = 0.036). The DEB had a quadratic relationship with serum anion gap (AG) (p = 0.002) and serum parathyroid hormone (PTH) content (p = 0.016). The DEB levels quadratically affected base excess (BE) in the plasma (p<0.001). In conclusion, the DEB unaffected growth performance but affected feed intake, N metabolism and some blood biochemical parameters of growing rabbits.

• Journal of Nutrition and Health
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• v.1 no.1
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• pp.19-25
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• 1968

In order to study the effect of source and level of the commonly used dietary fats on growth and metabolism of rats fed on low protein diet (rice diet) the weaning white rats were fed on various different experimental diets (see tables 1 and 2) during 11 weeks. The observations were made as follows : 1. Growth: (see table 3 and figures 1-9) In all dietary fats, among the 3 levels, 5% fat level is the best. Especially, the perilla oil group was remarkably good. 10% and 20% fat levels impaired the growth, consequently the growth rates of both 10% and 20% fat level groups were worse than those of Basal group (no fat added). However, 10% and 20% fat levels did not impaired the growth of VII group (10% soy flour added) In 5% fat level, the growth was good in sequence of perilla oil, tallow, sesame oil, soy oil and lard. 2. Feed consumption: (see table 3) In 20% fat level, the feed consumption was lowered. Generally, the feed consumption rate was proportional to the growth rate. In feed efficiency, 5% fat level was the best. 3. Liver weight: (see table 4) In liver weight per 100 G body weight, 20% fat level was the largest. This may be due to the poor body growth and liver fat accumulation. 4. Liver nitrogen: (see table 4) Generally, lower fat level groups showed liver nitrogen. Liver nitrogen is low in the groups of 20% fat level. 5. Liver fat: (see table 4) Generally, higher fat level groups showed higher liver fat. 6. Serum cholesterol: (see table 5) Generally, higher fat level groups showed higher serum cholesterol. Lard, sesame oil, and tallow groups showed higher level and soy oil and perilla oil groups showed lower level. Especially, perilla oil group showed remarkably lower level and VII group (10% soy flour added) showed lower level than VI group (same fat but no soy flour added).