Effect of water-saving irrigation regime on whole-plant yield and nutritive value of maize hybrids.

BACKGROUND: The effect of a water-saving irrigation regime on yield, chemical composition, rumen in situ dry matter disappearance (DMD) and neutral detergent fiber disappearance (NDFD), along with 7 h in vitro starch degradability (7 h IVSD), in maize hybrids selected for whole-plant silage making was investigated. A plot experiment was conducted in a continental climate location and four commercial maize hybrids (FAO class 700) were used in a completely randomized design with a factorial arrangement of irrigation treatments (fully irrigated (FI) and water-saving regime (WS)) and four replicates/treatment. The total amount of irrigation water was 494 mm in FI plots and 367 mm in WS plots, the latter achieved by skipping irrigations at vegetative growth stage, silking and blistering. RESULTS: Whole-plant yield, chemical composition, DMD, NDFD and 7 h IVSD slightly differed among hybrids and were not influenced by irrigation treatments. Plant dry matter content was lower in FI than WS plots (320 vs. 341 g kg⁻¹) , respectively; P < 0.05). Differences among hybrids were recorded for starch and acid detergent fiber contents (P < 0.05). CONCLUSIONS: The lack of differences on yield and nutritive value in tested maize hybrids grown under different water supply suggests the water-saving regime could be suitable for an optimal use of available water in maize management.

Immunological response in egg-sensitive adults challenged with cheese containing or not containing lysozyme.

OBJECTIVE: Lysozyme is an enzyme that hydrolyzes bacterial peptidoglicans. For this reason, it is used in cheese manufacturing in order to prevent a defect of long-ripened hard cheese called "late blowing" due to the outgrowth of spores of Clostridium tyrobutyricum and Clostridium butyricum. Moreover, germination of Listeria monocytogenes spores into vegetative cells is also sensitive to lysozyme. The enzyme can be an allergenic molecule, and for this reason there are concerns about its use in food industry. The immunological and clinical response of consumption of lysozyme-containing cheese has been evaluated in 25 egg-sensitive subjects with or without lysozyme sensitization. METHODS: A total of 25 egg-sensitive subjects were enrolled in this study. All the subjects were already treated for egg-sensitization and presented a positive skin prick test. All the subjects had a body mass index ≤ 25 kg/m(2) and were in the age range of 20-50 years. Each subject was studied twice and received randomly 30 g of Grana Padano (containing lysozyme) or TrentinGrana cheese (lysozyme-free) of two different aging periods: 16 or 24 months. A washout period of 1 week between each cheese intake was adopted. Blood samples were taken in fasting conditions and 1 hour after cheese intake and IgA, total IgE, and lysozyme-, ovomucoid-, and ovalbumin-specific IgE were measured. RESULTS: No adverse reactions were observed in both groups of patients after cheese samples were given. Lysozyme did not determine any variation of specific IgE compared with basal level. In lysozyme-sensitive patients a significant relationship between IgA and lysozyme-specific IgE was observed when lysozyme-containing cheese was given, confirming that lysozyme can pass the gut barrier. CONCLUSIONS: Neither adverse events nor immunological responses were observed after ingestion of cheese containing lysozyme. However, the immunological properties of peptides deriving from cheese protein hydrolysis need to be clarified, as does the effect of lysozyme on bacterial proteolytic activity.

Absence of allergic reactions to egg white lysozyme additive in Grana Padano cheese.

OBJECTIVE: The negative effects on cheese quality of milk contaminated by spores of Clostridium butyricum and Cl.tyrobutyricum is prevented by the use of egg white lysozyme as additive. Since the presence of lysozyme in cheese could be possibly risky in allergic subjects, we aimed at investigating its absorption as well as serum IgE antibody titers after ingestion of Grana Padano cheese, an Italian DPO, long-ripened hard cheese, in white egg allergic subjects. METHODS: Cheese lysozyme was measured by HPLC. Ten healthy volunteers and 20 patients with hen egg hypersensitivity, RAST positive (binding > or = 3%) to lysozyme and/or ovomucoid and ovalbumin received 15, 30 and 60 g of cheese at distance of at least 2 weeks each. Serum lysozyme was measured by ELISA and specific IgE binding to lysozyme by the radioallergosorbent test (RAST). RESULTS: The concentration of lysozyme in cheese was 155 +/- 5 mg/kg. The area-under-the-curve of serum lysozyme after 15 g of cheese was 244.5 +/- 14.0 in controls and 330.2 +/- 9.9 in patients (p < 0.01). Similar results were obtained with 30 and 60 g of cheese. Only 3 patients (15%) showed positive IgE antibody responses to cheese (overall RAST mean 4.45 +/- 1.25 % vs. 4.24 +/- 1.02 % baseline, p = ns). CONCLUSIONS: The amount of lysozyme absorbed with cheese was globally very low, although it was significantly lower in healthy controls than in allergic patients, where it induced an increase of IgE RAST score in 15% of subjects, without any clinical reaction. Therefore, the use of lysozyme as additive in Grana Padano cheese, does not appear to be harmful in egg allergic subjects.