Lucia Fiorentini

Determination of nitrogen intestinal digestibility in ruminants

The aim of this study was to compare two procedures used to estimate post-abomasal availability of feedstuff proteins in ruminants: (1) nitrogen disappearance from intestinal nylon bags; (2) true intestinal digestibility (dr). Dietary amino acid supplies and digestibilities were also evaluated. Three Italian Holstein rumen- and duodenum-fistulated cows were used. Animals were fed at an energy level equal to 1.7 times the maintenance requirement. Of the 29 proteic feedstuffs tested, 19 had intestinal digestibilities of over 90%: 17 of these were of vegetable origin and two were of animal origin. Nylon bag intestinal protein disappearances were over 90% for only 11 feedstuffs. Eighteen feedstuffs did not show any differences between the two procedures, while intestinal digestibility appeared superior to protein disappearance in ten raw materials (the opposite result was obtained in only one feedstuff). Amino acid intestinal digestibilities corresponded to source protein composition.

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≥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.

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.

Response on yield and nutritive value of two commercial maize hybrids as a consequence of a water irrigation reduction

The present study investigated in a practical farm condition the response of two commercial maize hybrids (maturity class FAO rating 700) grown for silage production on chemical composition and digestibility of whole maize plant as consequence of a severe water irrigation reduction. Based on different irrigation applications, water restricted (WR) and fully irrigated (FI) plots received 50 and 200 mm of irrigation water, respectively. A split-plot factorial arrangement in a randomised complete block design with two main plots (WR and FI) and two sub-plots (hybrid A and B) with 12 replications/treatment was performed. Studied parameters were dry matter (DM) yield, harvest index (HI), chemical composition, rumen in situ DM and neutral detergent fibre disappearance (DMD and NDFD, respectively), indigestible NDF (iNDF), 7h in vitro starch degradability (7hIVSD) and net energy (NE) for lactation content. Total DM and grain yields, HI and chemical composition differed (P<0.05) between FI and WR crops and only slight differences were recorded between hybrids. When compared to FI plants, WR had lower starch and higher fibre contents (P<0.05). Higher DMD (59.2 vs 56.4% DM) and NDFD (61.0 vs 58.4% NDFOM) were measured for FI with respect to WR crops, whereas iNDF was about 36% higher (P<0.05) in WR than FI. Lastly, WR plants had a lower NE content than FI plants (P<0.05). Our research showed that a drastic reduction in water irrigation negatively affected whole plant yield, chemical composition and nutrient availability of forage maize.

Anticatabolic activity of alpha-ketoglutaric acid in growing rats

This study evaluated the anti-catabolic effect of α-ketoglutaric acid (AKG) in rats. Thirty Sprague Dowley male rats were divided into 3 groups of 10 animals each and fed ad libitum with protein-free diet (PFD) supplemented with 0, 3, and 6 g/kg feed of AKG for 14 consecutive days. The AKG administration had no effect on the growth performance of rats in the global trial period (0–14 d). After 7 d of excreta collection, the losses of endogenous nitrogen (N), both urinary and total, linearly reduced (P<0.05) following the administration of AKG, ranging from 35.00 mg/d to 28.00 mg/d, and from 45.28 mg/d to 36.36 mg/d, respectively. The villi and microvilli heights were lower when animals received 3 g/kg of AKG respecting to other tested AKG levels. Indeed, enterocytes length linearly increased (P<0.05) as the level of AKG increased in the diet by 25.0% (3 g/kg) and 49.0% (6 g/kg). The AKG levels quadratically influenced (P<0.05) the essential amino acids (EAA) concentrations in the blood, being EAA lower for animals treated with 6 g/kg of AKG (−21.6%) compared to the animals fed the control PFD and the PFD with 3 g/kg of AKG. In conclusion, AKG was effective in reducing catabolism and EAA depletion.

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/m2 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.