Impacts of Age, Genotype and Feeding Low-Protein Diets on the N-Balance Parameters of Fattening Pigs

The effects of feeding low-protein (LP) diets and the age and genotype of fattening pigs were evaluated in an N-balance trial. Sixty weaned piglets of two genotypes were allotted to three different diets. Besides the control diets for the crossbred Topigs 20 × DanBred Duroc (TD) and Hungarian Large White (HLW) pigs, two LP diets were fed containing 1.5 (T1.5) and 3% (T3) less dietary protein than the control. The LP diets were supplemented with crystalline lysine, threonine, tryptophan, and methionine to equalize their digestible amino acid contents. Starter diets were fed between 20–30, grower I between 30–40, grower II between 40–80 and finisher between 80–110 kg live weights. Pigs were kept in floor pens, with 10 animals per pen. In all phases, six pigs with similar live weight were placed into individual balance cages and in the frame of a seven-day long balance trial, the daily N-intake, fecal and urinary N-excretion were measured. From the data N-digestibility, the total ammoniacal nitrogen (TAN) and N-retention were calculated. All the investigated main factors, the genotype and age of pigs and the protein content of the diets had significant effects on the N-balance of fattening pigs. The determinacy of the factors depended on the investigated parameter. Fecal N-excretion and N-digestibility were steadier compared with the urinary N-exertion and TAN percentage. N-digestibility increased and the urinary N-excretion decreased when LP diets were fed. The urinary N-decreasing effect of LP diets was not linear. Compared with the control (19.6 gN/day), T1.5 treatment resulted in 14.5, treatment T3 in 12.4 g daily urinary N-excretion. The TAN and the N-retention of HLW pigs were more favorable than those of TD pigs. Based on our results, it can be concluded that the accuracy of the nitrogen and TAN excretion values of pigs, used in the calculation of the national NH3 inventories, could be improved if the genotype, the more detailed age categories and the different protein levels of feeds are considered.

High Carbon Amendments Increase Nitrogen Retention in Soil After Slurry Application—an Incubation Study with Silty Loam Soil

Excess nitrogen (N) after animal slurry application is a persistent problem of intensive agriculture, with consequences such as environmental pollution by ammonia (NH3) and nitrous oxide (N2O) emissions and nitrate (NO3−) leaching. High-carbon organic soil amendments (HCAs) with a large C:N ratio have shown the potential of mitigating unintended N losses from soil. To reduce gaseous and leaching N losses after the application of slurry, a laboratory incubation study was conducted with silt loam soil. We tested the potential of three different types of HCA—wheat straw, sawdust, and leonardite (application rate 50 g C L−1 slurry for each of the three HCAs)—to mitigate N loss after amendment of soil with pig and cattle slurry using two common application modes (slurry and HCA mixed overnight with subsequent addition to soil vs. sequential addition) at an application rate equivalent to 80 kg N ha−1. Compared to the control with only soil and slurry, the addition of leonardite reduced the NH3 emissions of both slurries by 32–64%. Leonardite also reduced the total N2O emissions by 33–58%. Wheat straw reduced N2O emissions by 40–46%, but had no effect on NH3 emission. 15 N labeling showed that the application of leonardite was associated with the highest N retention in soil (24% average slurry N recovery), followed by wheat straw (20% average slurry N recovery). The mitigation of N loss was also observed for sawdust, although the effect was less consistent compared with leonardite and wheat straw. Mixing the slurry and HCA overnight tended to reduce N losses, although the effect was not consistent across all treatments. In conclusion, leonardite improved soil N retention more effectively than wheat straw and sawdust.

Effects of Dietary Supplementation with 2-Hydroxy-4-(methylthio)-butanoic Acid Isopropyl Ester as a Methionine Supplement on Nitrogen Utilization in Steers

The objective of the experiment was to investigate the effects of dietary supplementation with 2-hydroxy-4-(methylthio)-butanoic acid isopropyl ester (HMBi) on the nitrogen (N) metabolism in beef steers. The plasma metabolites analyzed by metabolome profiling were used to clarify the impact mechanism. Three Simmental steers (body weight, 593 ± 23 kg) were used as experimental animals. Three levels of HMBi (i.e., 0, 12, and 24 g d−1) were added in a basal ration as experimental treatments. The steers and the dietary treatments were randomly allocated in a 3 × 3 Latin square design. The results showed that supplementing HMBi up to 24 g d−1 did not affect the N retention and N retention rate (NRR), and the fecal N/urinary N ratio even though it tended to linearly increase the uric acid N/urinary N ratio in steers. The results of plasma metabolome profiling showed that supplementing HMBi at 24 g d−1 upregulated the plasma concentrations of L-methionine (Met); Met-related metabolites including betaine, Met sulfoxide, and taurine; and L-isoleucine and tyrosine, whereas it downregulated L-serine, glycine, diaminopimelic acid, and other metabolites. The reason for the nonsignificant effect of HMBi on improving the N utilization in steers could be that the steers used in the experiment were in the fattening period. It is suggested to evaluate the effects of the dietary addition of HMBi using growing cattle in further research.

An investigation on faecal N and lipid excretions in growing broilers fed false yam (Icacina oliviformis) tuber meal

This study was conducted to determine the effect of False Yam (Icacina oliviformis) on the growth performance, some biochemical alterations of growing broiler. For this experiment, 50, 20-day old growing broilers were randomly allocated to five dietary treatments: Raw tuber- (without alcohol treatment) @ 6%, raw tuber (70% alcohol treated) @ 6%, raw tuber @ 9%- were incorporated in a maize-soy based diet while commercial practical diet was used as control diet. Both control and treatment group were fed 60 gm feed daily (restricted feeding) up to the end of the experiment. The completely randomized design of the experiment was used. Pre-treatment of the meal with ethanol resulted in a significant increase in N intake and apparent digestibility and as well as the body weight gain. However, the Blood Urea Nitrogen (BUN) was found to be increased as compared to those non-alcohol and control groups. Broilers fed on diet based on 9% of the soaked tuber showed an elevated level of fat excretion as compared to those of others. Although, false yam supported the growth, however, apparent N retention could not have been improved by pre-treatment with alcohol and thus, the growth well below those expected. This was partly due to depression in digestion of the false yam protein and possibly to the presence of ant-nutritional factors in the meal that interfered with digestion, absorption and retention of N and lipid. The results showed that there was a significant decline (p<0.05) in the values of weight gain as the levels of false yam was increased in the diet. The results also showed that false yam may be added to broiler diets less than 6% without any detrimental effects. Furthermore, false yam may have contained potentially nephrotoxic agents that have been made- available for absorption due to ethanol treatment. Possible involvement of fibre and flatus compounds may have been linked to reduced N retention in broilers.

Increasing dietary proportion of wheat grain in finishing diets containing distillers' grains: impact on nitrogen utilization, ruminal pH, and digestive function

Because of its high crude protein (CP) content, dietary inclusion of corn dried distillers' grains with solubles (DDGS) in finishing cattle diets can increase the ruminal loss of ammonia-nitrogen (NH3-N), which ends up excreted as urine urea-N (UUN). Increasing dietary fermentable energy supply can enhance ruminal use of N; however, it could also lead to acidotic conditions that compromise digestive function and animal performance. We evaluated the effects of partially replacing dietary corn grain with 20 or 40% (dry matter [DM] basis) wheat grain in finishing diets containing 15% corn DDGS on N utilization, ruminal pH and digestive function. Nutrient intake and digestion, ruminal fermentation characteristics, microbial protein synthesis, route of N excretion, and blood metabolites were measured. Six ruminally-fistulated crossbred beef heifers (initial BW ± SD; 797 ± 58.8 kg) were used in a replicated 3 × 3 Latin square design with 28-d periods. Dietary treatments were either corn (73% of diet DM; CON), 53:20 corn:wheat blend (20W) or 33:40 corn:wheat blend (40W) as the major fermentable energy source. Dry matter intake tended to be lower for heifers fed the 40W than CON and 20W diets. Feeding diets containing wheat grain led to an increase (P = 0.04) in NDF intake. However, there was no diet effect (P ≥ 0.60) on apparent total tract DM and NDF digestibility. Feeding wheat grain led to a decrease (P ≤ 0.03) in mean and minimum pH, an increase (P = 0.04) in pH &lt; 5.8 duration, and a tendency for an increase in the area and acidosis index for pH &lt; 5.8 and 5.5. Nitrogen intake, which was lower (P = 0.04) for 40W than 20W heifers did not differ between CON and 20W heifers. There was no diet effect (P = 0.80) on ruminal NH3-N concentration and estimated microbial N flow. However, feeding diets containing wheat grain led to a decrease (P = 0.045) in UUN excretion (% total urine N). Fecal and total N excretion (% of N intake) increased (P &lt; 0.01) following the addition of wheat grain to the diet. Apparent N retention was lower (P = 0.03) for 40W than CON and 20W heifers. In summary, although it led to a desirable decrease in UUN excretion, feeding wheat grain in corn DDGS-containing diets increased acidotic conditions in the rumen, which possibly led to the tendency for a decrease in DMI. The negative apparent N retention at the 40% wheat grain inclusion also suggests a decrease in nutrient supply, which could compromise feedlot performance.

Effects of supplemental D-methionine in comparison to L-methionine on nitrogen retention, gut morphology, antioxidant status, and mRNA abundance of amino acid transporters in weanling pigs

A N-balance experiment was conducted to test the hypothesis that D-Methionine (D-Met) has the same bioavailability and efficacy as L-Methionine (L-Met) when fed to weanling pigs. A Met-deficient basal diet containing 0.24% standardized ileal digestible (SID) Met was formulated. Six additional diets were formulated by adding 0.036, 0.072, or 0.108% D-Met or L-Met to the basal diet, and these diets, therefore, contained 77, 87, or 97% of the requirement for SID Met. Fifty-six barrows (10.53 ± 1.17 kg) were housed in metabolism crates and allotted to the 7 diets with 8 replicate pigs per diet. Feces and urine were collected quantitatively with 7-d adaptation and 5-d collection periods. Blood and tissue samples from pigs fed the basal diet and pigs fed diets containing 0.108% supplemental Met were collected on the last day. Results indicated that N retention (%) linearly increased (P &lt; 0.01) as supplemental D-Met or L-Met increased in diets. Based on N retention (%) as a response, the linear slope-ratio regression estimated the bioavailability of D-Met relative to L-Met to be 101% (95% confidence interval: 57 to 146%). The villus height and crypt depth in the jejunum were not affected by Met level or Met source. Total antioxidant capacity or thiobarbituric acid reactive substances concentrations in plasma or tissue samples from pigs fed the control diet or diets containing 0.108% supplemental D-Met or L-Met were not different. Abundance of mRNA for some AA transporters analyzed in intestinal mucosa of pigs also did not differ. Therefore, it is concluded that D-Met and L-Met are equally bioavailable for weanling pigs.

Addition of cellulolytic bacteria in complete feed block based on agro-industrial by-products for Kacang goats

The research aimed at assessing the effects on nutrient digestion and ruminal fermentation by goats of a complete feed block (CFB) that incorporated agro-industrial by-products that were high in fibre and cellulolytic bacteria. Three Kacang goats, a native Indonesian breed, were used in a 3 × 3 Latin square experimental design with i) CFB without microbes (control), ii) CFB containing 1% Pseudomonas aeruginosa and 1% Acinetobacter baumannii, and iii) CFB containing 2% P. aeruginosa and 2% A. baumannii. Microbes in the CFBs consisted of lactic acid bacteria, yeast and cellulolytic bacteria that ranged from 106 to 108 cfu/g. The goats were fed each day at 08h00 and 16h00. The inclusion of P. aeruginosa and A. baumannii at 2% level reduced both neutral detergent fibre (NDF) and acid detergent fibre compared with other treatments. Goats fed on CFB with microbes had higher (P <0.01) digestibility of organic matter (OM) and NDF compared with control. The addition of P. aeruginosa and A. baumannii at 2% level increased (P <0.05) ruminal ammonia nitrogen (N-NH3), acetate, and total VFA. However, goats fed on CFB with microbes had lower (P <0.05) urinary N excretion, which improved (P <0.05) N retention compared with the control. It was concluded that a combination of lactic acid bacteria, yeast and cellulolytic bacteria in the CFB could modify fermentation in the rumen and increase the use of nitrogen in goats.

Feed protein utilization and nitrogen emission of young and mature Kejobong goats fed different ratios of concentrate and forage

This study aimed to evaluate feed protein utilization and nitrogen emission of young and mature Kejobong goats fed different concentrations of concentrate and forage. Sixteen heads of male Kejobong goats consisted of eight heads young goats (5 months old) and eight heads mature goats (9 months old) with initial body weight (BW) of 14 ± 1.46 kg, and 22.3 ± 1.99 kg, respectively were arranged in a nested design. All goats were fed with two different rations of concentrate and forage (C30 = 30% concentrate: 70% forage and C70 = 70% concentrate: 30% forage). The data were analyzed using ANOVA procedure. This study showed that the average daily gain (ADG) did not differ (p>0.05) in both ages, but it differed (p<0.05) in concentrate levels. The ADG of goats fed C70 was significantly higher (p<0.05) than those of goats fed C30 in both ages. The digestible crude protein (DCP) of young and mature goats was similar (p>0.05), while there was a significantly difference (p<0.05) between the treatments. There were no effects of different ages of goats and concentrate levels on feed conversion ratio (FCR) (p>0.05). The different ages of goats and concentrate levels affected N retention (g/day) and total N2O emission (g/day). It was concluded that ADG, DCP and FCR did not differ in mature and young Kejobong goats, while young goats had less N2O emissions than mature goats. Goats fed 70% of concentrate improved their ADG, DCP, N retention (g/day) and produced less N2O emission.

Application of Apparent Metabolizable Energy versus Nitrogen-Corrected Apparent Metabolizable Energy in Poultry Feed Formulations: A Continuing Conundrum

In the present investigation, N retention, AME, and AMEn data from six energy evaluation assays, involving four protein sources (soybean meal, full-fat soybean, rapeseed meal and maize distiller’s dried grains with solubles [DDGS]), are reported. The correction for zero N retention, reduced the AME value of soybean meal samples from different origins from 9.9 to 17.8% with increasing N retention. The magnitude of AME penalization in full-fat soybean samples, imposed by zero N correction, increased from 1.90 to 9.64% with increasing N retention. The Δ AME (AME minus AMEn) in rapeseed meal samples increased from 0.70 to 1.09 MJ/kg as N-retention increased. In maize DDGS samples, the correction for zero N retention increased the magnitude of AME penalization from 5.44 to 8.21% with increasing N retention. For all protein sources, positive correlations (p < 0.001; r = 0.831 to 0.991) were observed between the N retention and Δ AME. The present data confirms that correcting AME values to zero N retention for modern broilers penalizes the energy value of protein sources and is of higher magnitude for ingredients with higher protein quality. Feed formulation based on uncorrected AME values could benefit least cost broiler feed formulations and merits further investigation.