Feed intake, milk composition and cheese-making properties in Girgentana grazing goats with different genotype at as1-casein and k-casein

Milk ability for cheese manufacturing depends on both animals utilization of dietary nutrients and genetic polymorphism of caseins. It is well known that strong alleles associated with high content of as1-casein increase cheese-making properties of goat milk, whereas there is little information about effect of genetic variants of κ-casein. The aim of this experiment was to investigate the effect of some composite as1-casein and κ-casein genotypes n changing feeding behavior at pasture and milk yield and properties of Girgentana goats. Forty goats were genotyped at as1, as2, b and κ-casein loci using specific PCR protocols at DNA level and IEF technique at milk protein level. Twelve goats, differing only for as1-casein and κ-casein genotype and averaging 136±5 days in milk and 38±6 kg of live weight, were selected and divided equally into 3 groups according to their genotypes: WA, with weak alleles (FF) for as1-casein and AIEF for κ-casein; SA, with strong alleles (AA) for s1-casein and AIEF for κ-casein; SB, with strong alleles (AA) for as1-casein and BIEF for κ-casein. No goats with weak alleles for as1-casein and BIEF for κ-casein were found. Over a 5 weeks period in spring, goats were allowed to graze daily an Italian ryegrass and berseem clover mixture, and supplied with 500g/d of barley. Measurements, sampling and analyses of individual milk and forage selected by goats were performed weekly. Forage intake of goats at pasture was assessed by n-alkane technique. Data were analysed by MIXED procedure of SAS 9.1.3, using a model with genotype as fixed effect and goat as random effect. The genotype did not influence the goats intake of DM (1180,1137, 1250 g/d DM for WA, SA, SB), net energy, crude protein and NDF, and milk yield (994, 1104, 1130 g/d for WA, SA, SD). Milk casein increased passing from WA to SA and SB genotypes (2.66, 2.93, 3.33%; P<0.01), similarly to casein/fat ratio (0.66, 0.74, 0.79%; P<0.05). the genotype associated with high as1-casein was responsible of a reduction in whey protein (0.71, 0.49, 0.55% for WA, SA, SB; P<0.01) and an increase in the casein N/NT ratio (71, 79, 80 for WA, SA, SB; P<0.001). The values of casein N/N intake ratio (109, 143, 158 g/kg for WA, SA, SB; P<0.001) indicate an effect of strong alleles of as1-casein in improving the efficiency of dietary N utilization for milk casein synthesis. Milk from WA genotype showed higher pH (6.70, 6.63, 6.58; P<0.05) and lower titratable acidity (3.15, 3.55, 3.76 °SH/50ml; P<0.05) than SB milk, with intermediate values for SA genotype. Clotting time (r) (10.7, 10.5, 9.3 min for WA, SA, SB; P<0.05) and curd firming time (k20) (1.56, 1.56, 1.24 min for WA, SA, SB; P<0.001) were lower in milk from goats with BIEF for κ-casein than in milk from goats with AIEF, regardless of as1-casein alleles. Curd firmness (a30) was improved by strong alleles than weak alleles of as1-casein, and more by BIEF than AIEF for κ-casein (41.8, 51.1, 59.8 mm for WA, SA, SB; P<0.001). These first results suggest that the strong alleles of as1-casein could act at metabolic level by increasing the efficiency of dietary nitrogen utilization and, consequently, the milk casein synthesis, and evidence the additional role of BIEF alleles of κ-casein in increasing casein content and improving coagulation properties of goats milk, but require further investigation to be confirmed

Persistence of wild Streptococcus thermophilus strains on wooden vat and during the manufacture of a traditional Caciocavallo type cheese

The present work was undertaken to evaluate the influence of the wooden dairy plant equipment on the microbiological characteristics of curd to be transformed into Caciocavallo Palermitano cheese. Traditional raw milk productions were performed concomitantly with standard cheese making trials carried out in stainless steel vat inoculated with a commercial starter. Milk from two different farms (A and B) was separately processed. The wooden vat was found to be a reservoir of lactic acid bacteria (LAB), while unwanted (spoilage and/or pathogenic) microorganisms were not hosted or were present at very low levels. All microbial groups were numerically different in bulk milks, showing higher levels for the farm B. LAB, especially thermophilic cocci, dominated the whole cheese making process of all productions. Undesired microorganisms decreased in number or disappeared during transformation, particularly after curd stretching. LAB were isolated from the wooden vat surface and from all dairy samples, subjected to phenotypic and genetic characterization and identification. Streptococcus thermophilus was the species found at the highest concentration in all samples analyzed and it also dominated the microbial community of the wooden vat. Fourteen other LAB species belonging to six genera (Enterococcus, Lactobacillus, Lactococcus, Leuconostoc, Streptococcus and Weissella) were also detected. All S. thermophilus isolates were genetically differentiated and a consortium of four strains persisted during the whole traditional production process. As confirmed by pH and the total acidity after the acidification step, indigenous S. thermophilus strains acted as a mixed starter culture

Un caso di incidentaloma surrenalico: sintesi delle indicazioni e limiti della terapia chirurgica

Con il termine di “incidental mass” si identifica qualsiasi massa, scoperta occasionalmente con tecniche di imaging, in assenza di una sintomatologia specifica. Nel 1982 il termine di “incidentaloma” venne introdotto per indicare le lesioni surrenaliche di riscontro occasionale. Le percentuali di incidenza variano dal 10% ed al 25% di tutti i pazienti sottoposti ad ecotomografia, TC e RMN. È indubbia l’opportunità di formulare un adeguato protocollo diagnostico che, in considerazione dell’incerto inquadramento fisiopatologico, renda agevoli l’identificazione ed il trattamento precoce delle lesioni funzionanti e di quelle maligne o potenzialmente tali. Gli incidentalomi con un diametro inferiore a 1 cm sembrano non avere significato patologico e sono considerati come una manifestazione dell’involuzione della ghiandola in soggetti di età avanzata e possono restare per molto tempo misconosciuti. L’uso di tecniche diagnostiche per immagini ha reso possibile l’identificazione di queste masse, anche se di piccole dimensioni, nel corso di indagini diagnostiche effettuate con indicazioni diverse. Le dimensioni della massa sono un parametro ritenuto fondamentale per discriminare le lesioni benigne da quelle maligne. La maggior parte degli Autori ritiene assai sospette di malignità le masse di dimensioni superiori a 5-6 cm, mentre considera benigne quelle di diametro inferiore ai 3 cm. Restano mal definibili tutte le altre che vengono valutate e trattate secondo criteri non perfettamente codificati

Effects of grazing Trifolium subterraneum and Lolium multiflorum in various proportions on forage intake and milk production of dairy ewes

The aim of this research was to evaluate the effects of grazing Trifolium subterraneum (T) and Lolium multiflorum (L), as pure or associated crops, on forage intake and milk yield and composition in Comisana ewes. The four following fenced subplots, each of 2500 m2, were used for grazing: T, 100% of surface; L, 100% of surface; TL, T and L on 66.6 and 33.3 % of surface; LT, T and L on 33.3 and 66.6% of surface, respectively. Each subplot was divided into two parcels in order to have two replicates. Forty ewes were divided into eight homogeneous groups, with regard to milk yield, days in milk and live weight. In spring for 70 days, each group grazed daily for 8 h one of the fenced parcels. Measurements, sampling and analyses regarded the available forage, dry matter (DM) intake (assessed by the n-alkane technique) and milk yield of ewes. Data were analysed for the effect of grazed forage using the GLM procedure of SAS. The clover produced a higher amount of biomass than ryegrass, due also to the higher ryegrass intake of the ewes. Herbage DM intake was lower for the L group than the other (1090 vs 1552, 1520 and 1427 g/d for L, T, TL and LT, respectively; P<0.01). Consequently, the diet affected milk yield which was lower for L ewes than for T, TL and LT groups (740 vs 924, 964 and 898 g/d; P<0.05). The exclusive use of ryegrass in the diet led to a tendency to decrease protein, casein and urea contents in milk. Moreover, L milk was higher in curd firming time (k20: 3.39, 1.68, 1.85 and 2.20 min for L, T, TL and LT, respectively; P<0.05) and lower in curd firmness (a30: 20.4, 40.3, 42.6 and 35.2 mm for L, T, TL and LT, respectively; P<0.05). In conclusion, the use in any proportion of Trifolium subterraneum showed to increase both DM intake and milk production of dairy ewes