Effects of methionine sources on nitrogen retention in growing pigs
Supplementing a methionine-deficient and reduced crude protein diet with either 65 parts DL-methionine (DL-Met) or 100 parts MHA-Ca on a product-to-product basis resulted in similar nitrogen retention. No significant differences were observed when nitrogen retention was expressed as grams per day, percentage of intake, or percentage absorbed.
Using the nitrogen-balance method, we validated that nitrogen retention, a highly sensitive parameter, was not affected by methionine sources when used at a 65:100 ratio (DL-methionine to MHA-product). This confirms that the efficacy of MHA relative to DLM is 65%.
Professor, University of Illinois, USA
To determine the nitrogen retention of pigs fed a reduced crude protein diet supplemented with 65 parts of DL-Met or 100 parts of MHA-Ca on a product basis.
Location: Swine Research Center, University of Illinois at Urbana-Champaign
Project team leaders: Prof. Dr. Hans Stein, Dr. John Htoo, Dr. Maria Mendoza
| Animals | Thirty barrows (initial body weight: 16.37 ±1.28 kg, PIC Genetics) |
| Design | Completely randomized block design with 6 replicants per treatment |
| Housing | Individually, in metabolism crates |
| Diets | Basal diet: Dietary treatments: |
| Feeding | Feed was provided at 3.2 times the energy requirement for maintenance, split into 2 equal daily meals (at 0800 and 1600 h); pigs had ad-libitum access to water |
| Parameters | Pig feed intake and body weight gain; dry matter of the fecal and diet samples; nitrogen content of fecal, urine and diets samples |
| Duration | 7 days adaptation to the diets, and 4 days collection (urine and feces) |
Trial results
- Pigs fed 65 parts MetAMINO® or 100 parts MHA-CA on product basis did not differ in final body weight (BW), feed intake, and N intake (Table 1).
- Urine N excretion decreased as methionine sources increased in the diet, regardless of the source (data not shown).
- Nitrogen utilization, reflected by plasma urea nitrogen (PUN), improved linearly as methionine sources increased in the diet, regardless of the methionine source (Table 2).
- Nitrogen retained (g/d) tended to be greater for diets supplemented with methionine sources while the highest N retention (g/d) was achieved in pigs fed diet supplemented with 0.09 % MetAMINO® (Table 2).
- Nitrogen retention (% of absorbed) linearly increased regardless of the methionine source when used in a MetAMINO® to MHA-Ca ratio of 65 to 100 on product basis (Figure 1).
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