• Asian-Australasian Journal of Animal Sciences
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• v.11 no.6
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• pp.718-724
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• 1998

Twelve gilts were used to investigate the effect of lysine to protein ratio (5.2 g lysine/100 g CP vs. 6.7 g lysine/100 g CP) in practical diets on nitrogen retention and the efficiency of utilization in growing pigs. Treatments involved 2 levels of dietary lysine (5.2 or 6.7 g/100 g CP) and 3 levels of dietary crude protein (11, 14 and 17% in diet). Nitrogen retention was greatest when pigs were fed the control diet containing 17% protein. Nitrogen retention progressively increased as dietary protein increased (p < 0.01), but it was not affected by lysine concentration (g/100 g CP). Apparent biological value (ABV, nitrogen retained/apparently digestible nitrogen) was estimated to be ~50% at the maximum nitrogen retention. ABV was not affected by lysine concentration, but declined (p < 0.05) as the dietary protein level increased. The efficiency of intake N used for maximum nitrogen retention was approximately 44%. One gram of lysine supported approximately 9 to 10 g apparent protein accretion (nitrogen retention ${\times}$ 6.25/lysine intake) in pigs fed control diets. The efficiency of lysine utilization for protein accretion was lower in pigs fed high-lysine diets (6.7 g lysine/l00 g CP) so that 1 g of lysine accounted for 7 to 8 g of protein accretion in these pigs (p < 0.01). The lysine required to support maximum nitrogen retention in pigs fed high-lysine diets was higher than that in pigs fed control diets, which suggests that lysine was over-fortified relative to crude protein, since practical diets can not be formulated without excess of some amino acids. In summary the concentration of 5.2 g total lysine/100 g CP in diet is more appropriate for corn-soybean diets than the commonly suggested the content of 6.7 g total lysine/100 g CP.

• Journal of Nutrition and Health
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• v.26 no.9
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• pp.1033-1048
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• 1993

This study was designed to describe the effect of the protein quality at different intake level of protein on the protein metabolism in the whole body of growing pigs with a simulation model. Varying to the protein level in feeds, four simulations were conducted. The feed protein level, represented as proportions of digestible protein to the metabolic energy (DP/ME, g/MJ), were 6-8, 11-13, 17-19, and 23-25 DP/ME, respectively. Two protein quality and six weeks of growth time were used at each simulation. The objective function for the simulations was protein deposition in the whole body, which was calculated from the experimental results. The parameters in the simulation were determined by the parameter estimation technique. The results obtained from the simulation were as follows: The protein synthesis and breakdown rates(g/day) in the whole body was increased with the increase of protein quality only at lower or required level of protein intake. They showed a parallel behavior in the course of growth, irrespective of quality and level of feed protein intake. The simulated protein deposition and protein synthesis showed a linear relationship between them at different protein quality and level. The affinity parameter showed a linear relationship between them at different protein quality and level. The affinity parameter showed that arginine, tryptophan and isoleucine were more efficient in the stimulation ofbody protein synthesis. Lysine and phenylalanine+tyrosine were less efficient. The oxidation parameter showed that histidine, pheyalanine+tyrosine were less efficient. The oxidation parameter showed that histidine, phenyalanine+tyrosine, and methionine+cystine were oxidized in larger magnitude than lysine and threonine. The oxidation parameter of most amino acids increased with the increase of protein intake beyond the requirement level, but not any more at highest protein intake level. Finally it was found that the improvement of feed protein quality at the lower or required level of protein intake increase protein deposition through a parallel increase of protein synthesis and breakdown.

• Animal Bioscience
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• v.35 no.10
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• pp.1592-1605
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• 2022

Objective: The objective of this study was to select an effective in vitro digestion-fermentation model to estimate the effect of decreasing dietary crude protein (CP) on odor emission during pig production and to suggest potential prediction markers through in vitro and in vivo experiments. Methods: In the in vitro experiment, three diet formulations with different CP contents (170 g/kg, 150 g/kg, and 130 g/kg) but containing the same standardized ileal digestible essential amino acids (SID-EAA) were assessed. Each diet was evaluated by two different in vitro gastric-intestinal phase digestion methods (flask and dialysis), combined with fresh pig feces-ferment inoculation. Eighteen growing barrows (31.9±1.6 kg) were divided into three groups: control diet (180 g CP/kg, without SID-EAA adjustment), 170 g CP/kg diet, and 150 g CP/kg diet for 4 weeks. Results: The in vitro digestion results indicated that in vitro digestibility was affected by the gastric-intestinal phase digestion method and dietary CP level. According to the gas kinetic and digestibility results, the dialysis method showed greater distinguishability for dietary CP level adjustment. Nitrogen-related odor compounds (NH₃-N, indole, p-cresol, and skatole) were highly correlated with urease and protease activity. The feeding study indicated that both EAA-adjusted diets resulted in a lower odor emission especially in p-cresol and skatole. Both protease and urease activity in feces were also closely related to odor emissions from nitrogen metabolism compounds. Conclusion: Dialysis digestion in the gastric-intestinal phase followed by fresh fecal inoculation fermentation is suitable for in vitro diet evaluation. The enzyme activity in the fermentation and the fecal samples might provide a simple and effective estimation tool for nitrogen-related odor emission prediction in both in vitro and in vivo experiments.

• Asian-Australasian Journal of Animal Sciences
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• v.11 no.2
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• pp.145-151
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• 1998

The possibility of using rice gruel compared to that of the cane molasses as a source of readily fermentable energy for a urea supplemented straw diet has been studied. Twelve native growing bulls of $237{\pm}8.7kg $ live weight and months old were randomly allocated to three treatments fed solely rice straw enriched with : (1) 3% urea (US), (2) 3% urea + 15% molasses (UMS) and (3) 3% urea + 30% rice gruel (UGS). The feeding trial continued for sixty days. Organic matter (OM) intake was significantly (p < 0.05) higher in the UMS ( $64g/kg\;W^{0.75}/d$) followed by UGS ($53g/kg\;W^{0.75}/d$) and US ($49g/kg\;W^{0.75}/d$). Estimated (from digestible OM intake) metabolizable energy (ME) intake were 396, 348 and $301kJ/kg\;W^{0.75}/d$ for UMS, UGS and US respectively. The maintenance (i.e., no change in live weight) ME intake calculated to be $308{\pm}7.4kJ/kg\;W^{0.75}/d$. Urinary purine derivatives excretion was nonsignificantly higher in the UMS (51.73 mmol/d), followed by UGS (42.53 mmol/d) and US (35.26 mmol/d). The estimated microbial N (MN) yield were 21.10, 14.00 and 11.60 g/d for UMS, UGS and US respectively. For each MJ increase in ME intade, MN yield increased by $1.29{\pm}0.134g$. Observed live weight changes during the experimental period were 292, 125 and -19 g/d respectively for UMS, UGS and US. It was concluded that supplementation of readily fermentable N (urea) alone was not enough to optimize the rumen function and a source of readily fermentable energy was required. Rice gruel was less effective than molasses as fermentable energy source to remove a restriction on voluntary intake and provide less amino acids of microbial origin for absorption from the small intestine, Thus more substrate for protein synthesis and gluconeogenesis were available for growth in the molasses than the rice gruel supplemented animals. However, in situation where molasses is not available or costly, rice gruel does appear to have a place as readily fermentable energy source on a urea supplemented straw diet.

• Korean Journal of Poultry Science
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• v.28 no.3
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• pp.245-257
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• 2001

Localization of livestock facilities leads to concentration of livestock wastes and subsequent leakage of pollutants into the environment, resulting in public concern about their effects. Nitrogen (N) and phosphorus (P) are the most harmful components of animal manure, but odor from the manure itself and the livestock facilities is also a problem. Improving the nutrient efficiency of the livestock helps to decrease excretion of these environmental contaminants. Pigs and chickens are the main experimental models used in studies to improve nutrient efficiency. Addition of feed supplements and modifying feeding systems to improve nutrient efficiency can result in significant decrease in the N, P, odor and dry matter (DM) weight of manure. Examples of these methods include the following. 1) Addition of synthetic amino acids and reducing protein contents resulted N reductions of 10∼27% in broilers, 18∼35% in chicks and layers, 19∼62% in pigs, and a 9∼43% reduction in odor in pigs. 2) Enzyme supplementation resulted in a 12∼15% reduction in DM weight in broiler manure. 3) Phvtase supplementation resulted in P reductions of 25∼35% in chickens and 20∼60% in pigs. 4) Use of growth promoting substances resulted in a 5∼30% reduction in N and a 53∼56% reduction in odor of pigs. 5) Formulating diets closer to requirements (diet modification) reduced N and P by 10∼15% each in chickens and pigs, and odor by 28∼ 79% in pigs. 6) Phase feeding reduced N and P excretion by chicken and pigs from 10∼33% and 10∼13% each, as well as odor in growing and finishing pigs by 49∼79%. 7) Use of highly digestible raw materials in feed reduced N and P excretion by 5% in chickens and pigs.

• Asian-Australasian Journal of Animal Sciences
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• v.12 no.7
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• pp.1096-1103
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• 1999

A study was conducted to clarify the impact of recombinant porcine somatotropin (pST) on the efficiency of absorbed nitrogen use for protein deposition in growing pigs. Three levels of dietary crude protein (9.0, 11.5, 14.0% CP) were used. Each had either a sub-optimum or near optimum lysine: CP concentration (Low-lysine, 3.8 g/100 g CP and High-lysine, 5.5 g/100g CP) in order to achieve different metabolic efficiencies for nitrogen deposition (ca. 45 vs. 60%). Twelve crossbred female pigs $(59{\pm}4kg\;BW)$ were placed in metabolism cages and fitted with bladder catheters. Each pig received an excipient injection daily for the first 10-d, a pST (5 mg/d) injection for the second 10-d, and then excipient for the last 10-d. Pigs were randomly assigned to one of six dietary treatments (2 pigs/diet) and fed 4 times per d at $92g/kg\;BW^{0.75}$ $(3{\times}maintenance)$. Means for the excipient period were compared to means for the pST period. Urinary nitrogen (N) output declined in pST-treated pigs (p<0.01) irrespective of dietary protein content or lysine level. Nitrogen retention increased by an average of 11% (p<0.01) with pST treatment (726 vs. $803mg\;N/kg^{0.75}\;BW/d$). Forty-eight percent of the absorbed N was retained with Low-lysine diets, but this increased to 53% with pST injection (+11%, p<0.01). Pigs fed High-lysine diets retained 62% of absorbed N which increased to 69% with pST (+11% p<0.01). the addition of lysine improved N use by 27% (High vs. Low, p<0.01), but the effect of lysine and pST was additive (+40%). Therefore, pST improves N retention and the efficiency of apparently absorbed N use in growing pigs (>60kg). It does so with diets having the potential for either low or high efficiencies of N use (48% and 62%). More work is needed to determine if the partial efficiency of N use improves in direct proportion to pST dose since the improvement in protein deposition is a function of pST dose.