Effects of porcine somatotropin administration on the responses to dietary lysine and a near-ideal blend of amino acids on the amino acid composition of whole-body protein and amino acid accretion rate in growing pigs.

An experiment was conducted to assess the effects of porcine somatotropin (pST) on the responses to a near-ideal blend of AA on the AA composition of empty, whole-empty body (WEB) protein and WEB essential AA accretion rate in pigs from 22 to 60 kg BW. Forty Hampshire × Yorkshire gilts were individually penned and assigned to a 4 × 2 factorial arrangement of treatments consisting of four diets with and without pST injection. A fortified corn-soybean meal basal diet was formulated to contain 1.50% total Lys with Thr, Met, and Trp added to obtain a near-ideal blend of these AA relative to Lys. In three additional diets, Lys was reduced to 1.25%, 1.00%, and 0.75% by diluting the basal diet with cornstarch, cellulose, and sand such that the diets also contained the same ratios of AA. Pigs that received pST were administered a daily i.m. injection of 2 mg of pST. At 60 kg BW, the WEB (carcass, head, viscera, blood, nails, and hair) was ground and analyzed for proximate and AA composition. Administration of pST increased (P < 0.001) accretion rates of WEB protein and essential AA. Increasing dietary essential AA increased (quadratic, P < 0.03) accretion rate of WEB protein, His, Leu, Trp, and Val in pST-treated pigs, but not in untreated pigs. Lysine composition in the accreted WEB protein was not affected (P > 0.05) by dietary Lys. The efficiency of Lys utilization for WEB Lys accretion was linearly affected (P < 0.01) by dietary Lys. These results indicated that the dietary Lys needed to achieve maximum WEB Lys accretion is markedly increased by pST administration.

This study evaluated the effects of two factors, porcine somatotropin and graded levels of amino acids, on the total accumulation and the accretion rate of amino acids across a broad range of protein deposition rates in growing pigs. Treatments included 1) with or without a daily injection of porcine somatotropin and 2) graded levels of total dietary lysine from 0.75% to 1.50%. As expected, both the administration of porcine somatotropin and increased dietary lysine increased both the amount and the rate of amino acid accretion. However, the amount and rate of amino acid accretion from increased dietary amino acids were markedly greater in pigs treated with porcine somatotropin. Thus, the extent to which the genetic potential for protein deposition is achieved depends on both the anabolic capacity of the pig and the amino acid concentration of the diet provided.

Selective atrophy of the cervical enlargement in whole spinal cord MRI of amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis (ALS) is a deadly neurodegenerative disorder affecting motor neurons in the spinal cord and brain. Studies have reported on atrophy within segments of the cervical cord, but we are not aware of previous investigations of the whole spinal cord. Herein we present our findings from a 3T MRI study involving 32 subjects (15 ALS participants and 17 healthy controls) characterizing cross-sectional area along the entire cord. We report atrophy of the cervical enlargement in ALS participants, but no evidence of atrophy of the thoracolumbar enlargement. These results suggest that MR-based analyses of the cervical cord may be sufficient for in vivo investigations of spinal cord atrophy in ALS, and that atrophy of the cervical enlargement (C4-C7) is a potential imaging marker for quantifying lower motor neuron degradation.

Challenges in developing nutrient guidelines for companion animals.

The purpose of the present review is to highlight some of the challenges and issues in developing nutritional guidelines for companion animals, and to provide some insights that may influence their future direction. For this purpose, we have chosen to provide a brief historical review of the development of dog and cat nutrient guidelines, and an analysis of current recommendations and of key institutions and bodies (notably the National Research Council) that are influential in defining nutrient guidelines for companion animals. In addition, we have also included a review of current approaches for defining nutritional guidelines for humans and farm animal livestock, as they provide differing perspectives and insights that may be instructive for the future development of nutritional guidelines for companion animals.