Lower Protein Intake Supports Normal Growth of Full-Term Infants Fed Formula: A Randomized Controlled Trial.

Infant formulas have been conventionally prepared with an excess of total protein in order to provide sufficient amounts of essential amino acids to the rapidly growing infant. However, this practice leads to higher than necessary protein intake during early infant development, inducing accelerated growth patterns correlated with the development of chronic diseases later in life. This study was aimed at assessing the safety of an infant formula enriched with bovine alpha-lactalbumin containing a total protein concentration very close to that of human milk, and determining its efficacy in the support of healthy infant growth from the first month to the fourth month of age. Healthy full-term infants ≤40 days of age were randomized in this controlled single blind trial to one of the following infant formulas: IF 1 (containing 1.0 g protein/dL; n = 30), IF 2 (containing 1.3 g protein/dL; n = 24), and IF 3 (containing 1.5 g protein/dL; n = 42). A control group consisting of exclusively breastfed infants (HM; n = 212) was included in the study. Anthropometric measurements and Z-scores were evaluated at baseline, at 1 month of age, and at 4 months of age. Weight gain (g/day) was similar in the IF 1 and the HM groups (p = 0.644), and it was significantly greater in the IF 2 and IF 3 groups than in the HM group. Growth patterns in both breastfed or IF-fed infants were in accordance with the World Health Organization (WHO) growth standards. At four months of age, the mean weight-for-age Z-score (WAZ) adjusted for initial value in the IF 1 group was similar to that of the HM group and significantly lower than that of the IF 2 and IF 3 groups (p = 0.031 and p = 0.014 for IF 2 and IF 3, respectively). Length-for-age (LAZ) adjusted for initial value was similar among all groups at four months of age. From 1 to 4 months of life, IF 1 containing 1.0 g protein/dL promotes growth and weight gain similar to those observed in exclusively breastfed infants. As this is a first approach to studying an IF containing total protein in a level below that recommended by international committees on nutrition, further investigations are needed to support these findings evaluating infant’s metabolic profile and growth in the long term.

Use of urea-polyacrylamide electrophoresis for discrimination of A1 and A2 beta casein variants in raw cow's milk.

Beta-casein (BC) in cow's milk occurs in several genetic variants, where BC A1 (BCA1) and BC A2 (BCA2) are the most frequent. This work deals with a method based on modified polyacrylamide gel electrophoresis using urea PAGE to discriminate BCA1 and BCA2 variants from Holstein Friesian (HF) and genetically selected Jersey A2/A2 (JA2) cow's milk. Two well defined bands were obtained from BC fraction of HF milk, while that of JA2 showed a single band. Proteins from these bands were sequenced by HPLC-quadrupole linear ion trap/mass spectrometry, resulting in BCA1 and BCA2 separation from the BC fraction of HF milk, whereas BCA2 was the only constituent of JA2 fraction. This method represents a feasible and useful tool to on site phenotyping of BC fraction of cow's milk for pharmaceutical and food industries applications.

Production of Cow's Milk Free from Beta-Casein A1 and Its Application in the Manufacturing of Specialized Foods for Early Infant Nutrition.

Beta-casein (BC) is frequently expressed as BC A2 and BC A1 in cow's milk. Gastrointestinal digestion of BC A1 results in the release of the opioid peptide beta-casomorphin 7 (BCM7) which is less likely to occur from BC A2. This work was aimed to produce milk containing BC A2 with no BC A1 (BC A2 milk) using genetically selected CSN2 A2A2 Jersey cows. Additionally, we aimed to develop an infant formula (IF) suitable for healthy full-term infants during the first six months of life based on BC A2 milk. The concentration of BCM7 released from BC A2 IF, from commercially available IFs as well as from human milk and raw cow's milk was evaluated after simulated gastrointestinal digestion (SGID). BC A2 IF presented the lowest mean relative abundance of BC A1 (IF 1 = 0.136 ± 0.010), compared with three commercially available IFs (IF 2 = 0.597 ± 0.020; IF 3 = 0.441 ± 0.014; IF 4 = 0.503 ± 0.011). Accordingly, SGID of whole casein fraction from BC A2 IF resulted in a significantly lower release of BCM7 (IF 1 = 0.860 ± 0.014 µg/100 mL) compared to commercially available IFs (IF 2 = 2.625 ± 0.042 µg/100 mL; IF 3 = 1.693 ± 0.012 µg/100 mL; IF 4 = 1.962 ± 0.067 µg/100 mL). Nevertheless, BCM7 levels from BC A2 IF were significantly higher than those found in SGID hydrolysates of BC A2 raw milk (0.742 ± 0.008 µg/100 mL). Interestingly, results showed that BCM7 was also present in human milk in significantly lower amounts (0.697 ± 0.007 µg/100 mL) than those observed in IF 1 and BC A2 milk. This work demonstrates that using BC A2 milk in IF formulation significantly reduces BCM7 formation during SGID. Clinical implications of BC A2 IF on early infant health and development need further investigations.

Steroid Receptors and Aromatase Gene Expression in Different Brain Areas of Copulating and Sexually Sluggish Male Rats.

INTRODUCTION: Sexually sluggish (SS) males have been identified in several species of mammals including rats. These animals take more than 30 minutes to ejaculate; they do not ejaculate or do so inconsistently despite being tested repeatedly with sexually receptive females. Different brain areas and hormones play an important role in the control of male sexual behavior. AIMS: Determine gene expression for the androgen receptor (AR), the estrogen receptor alpha (ERα), the progesterone receptor (PR), and the aromatase enzyme (ARO), in brain regions important in the control of male sexual behavior including the medial preoptic area (MPOA), the amygdala (AMG), the olfactory bulb (OB), and, as a control, the cortex (CTX) of copulating (C) and SS male rats. METHODS: Males that ejaculated within 30 minutes in three tests with receptive females were included in the C group, while those males that ejaculated in one or none of the four tests were included in the SS group. RNA was isolated 1 week after the last test of sexual behavior, and cDNA was synthesized from the brain areas listed above. MAIN OUTCOMES MEASURES: Expression of the AR, ERα, PR, and ARO genes was determined by quantitative polymerase chain reaction (qPCR). Cyclophilin A (CycA) and tyrosine 3-monooxygenase-tryptophan activation protein zeta (Ywhaz) were housekeeping genes used to determine relative gene expression with the 2(-ΔΔCt) method. RESULTS: The expression of mRNA for AR and ARO increased in the MPOA of SS males. ARO mRNA was increased in the AMG of SS males. In the OB, ERα mRNA was increased and AR mRNA reduced in SS males. CONCLUSION: These results indicate SS and C males show differences in gene expression within brain regions controlling sexual behavior.