Adriana Bonanno

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.

In vivo digestibility and nutritive value of Atriplex halimus alone and mixed with wheat straw

In vivo digestibility trials were carried out using six young rams fed with Atriplex halimus biomass harvested in summer (A) and in early autumn (B). and with a mixture of mid-autumn A triplex halimus and wheat straw (5:1 ratio on fresh matter basis) (C). Atriplex halimus had a high protein content (139.0, 135.9 and 193.4 g/kg DM in A, B and C respectively), but was rich in sodium chloride, especially in summer (145.9 g/kg DM), limiting its use as feed. The summer forage had a higher organic matter (OM) digestibility coefficient than the autumn forage (0.663 v. 0.530) but lower digestible OM intake (16.8 v. 29.4 g/day per kg BW 0.75 ). In autumn forage, the combination with straw did not influence the digestibility of organic matter, whereas it enhanced DOM intake in comparison with the Atriplex halimus on its own (35.7 v. 29.4 g/day per kg BW 0.75 ).

The influence of the wooden equipment employed for cheese manufacture on the characteristics of a traditional stretched cheese during ripening

The influence of the wooden equipment used for the traditional cheese manufacturing from raw milk was evaluated on the variations of chemico-physical characteristics and microbial populations during the ripening of Caciocavallo Palermitano cheese. Milk from two farms (A, extensive; B, intensive) was processed in traditional and standard conditions. Chemical and physical traits of cheeses were affected by the farming system and the cheese making technology, and changed during ripening. Content in NaCl and N soluble was lower, and paste consistency higher in cheese from the extensive farm and traditional technology, whereas ripening increased the N soluble and the paste yellow and consistency. The ripening time decreased the number of all lactic acid bacteria (LAB) groups, except enterococci detected at approximately constant levels (10(4) and 10(5) cfu g(-1) for standard and traditional cheeses, respectively), till 120 d of ripening. In all productions, at each ripening time, the levels detected for enterococci were lower than those for the other LAB groups. The canonical discriminant analysis of chemical, physical and microbiological data was able to separate cheeses from different productions and ripening time. The dominant LAB were isolated, phenotypically characterised and grouped, genetically differentiated at strain level and identified. Ten species of LAB were found and the strains detected at the highest levels were Pediococcus acidilactici and Lactobacillus casei. Ten strains, mainly belonging to Lactobacillus rhamnosus and Lactobacillus fermentum showed an antibacterial activity. The comparison of the polymorphic profiles of the LAB strains isolated from the wooden vat with those of the strains collected during maturation, showed the persistence of three enterococci in traditional cheeses, with Enterococcus faecalis found at dominant levels over the Enterococcus population till 120 d; the absence of these strains in the standard productions evidenced the contribution of vat LAB during Caciocavallo Palermitano cheese ripening.

Milk quality as affected by grazing time of day in Mediterranean goats.

We evaluated the effect of grazing time of day on goat milk chemical composition, renneting properties and milk fatty acid profile in a Mediterranean grazing system. Sixteen lactating Girgentana goats were divided into two experimental groups and housed in individual pens, where they received 500 g/d of barley grain. For 5 weeks the two groups were left to graze in two fenced plots on a ryegrass sward as follows: morning group (AM), from 9.00 to 13.00; afternoon group (PM), from 12.00 to 16.00. In selected herbage, water-soluble carbohydrates (WSC) increased in the afternoon (204 v. 174 g/kg dry matter, DM; P=0.01), whereas crude protein (CP) and linolenic acid decreased (respectively, 16.7 v. 19.8% DM; P<0.01 and 26.8 v. 30.4 g/kg DM; P<0.01). Pasture dry matter intake (DMI) was significantly higher in the afternoon (0.82 v. 0.75 kg/d; P=0.026). Fat corrected milk production (FCM), milk fat and lactose content were not affected by treatment, whereas protein and titrable acidity ( degrees SH) increased in the PM group (respectively 3.56 v. 3.42%; P=0.01; 3.55 v. 3.22 degrees SH/50 ml; P=0.01). In contrast, milk urea content was significantly higher in the AM group (381 v. 358 mg/l; P=0.037). The results seem to indicate that an improvement in ruminal efficiency might be obtained by shifting grazing time from morning to afternoon, as a consequence of a more balanced ratio between nitrogenous compounds and sugars. Indeed, the higher linolenic acid and the lower conjugated linoleic acid (CLA) (respectively 1.02 v. 0.90, P=0.037; 0.71 v. 0.81% of total fatty acids, P=0.022) in the milk of goats grazing in the afternoon seem to indicate a reduced biohydrogenation activity in the PM group.

Effects of Sulla forage (Sulla coronarium L.) on the oxidative status and milk polyphenol content in goats.

Twelve milking Girgentana goats were allocated into 3 groups and fed 3 diets ad libitum in a 3×3 Latin square design with 3 periods. The diets were Sulla fresh forage ad libitum (SUL), Sulla fresh forage ad libitum and 800g/d of barley meal (SULB), and mixed hay ad libitum and 800g/d of barley meal (HB). Changes were observed in total polyphenol intake, plasma oxidative status, plasma polyphenol content, metabolic status, milk polyphenol content, and total antioxidant capacity. The fresh forage diets (SUL and SULB) increased dry matter, total polyphenol, nontannic polyphenol and tannin intakes, and the milk total protein, casein, milk total polyphenols, and milk free polyphenols compared with the HB diet. The intake of condensed tannins was higher in the SUL than in the HB group, and an intermediate value was recorded for the SULB group. Plasma from the SUL- and SULB-fed goats exhibited greater total antioxidant capacity and greater total polyphenol and free polyphenol levels compared with the plasma from the HB group. Positive correlations between plasma total antioxidant capacity and condensed tannins intake (r=0.43), plasma total polyphenol and total polyphenol intake (r=0.61), and plasma free polyphenol and milk total polyphenols (r=0.38) were observed. The correlation between milk free polyphenols and whey total antioxidant capacity (r=0.42) highlights the role of free polyphenols in the determination of the antioxidant activity of milk. These results indicate that Sulla fresh forage exerts an antioxidant activity due to its secondary compounds that provide additional antioxidant value and that Sulla forage appears to be a promising strategy for improving product quality.

Intake and milk production of goats grazing Sulla forage under different stocking rates

Abstract A total of 24 Girgentana goats was divided into 3 homogeneous groups grazing a sulla monoculture under stocking rate of 30, 50 or 70 goats/ha (LSR, MSR and HSR). Available biomass, herbage selected by goats and milk yield were measured and sampled. The DM intake of goats and its botanic composition and digestibility were assessed by the n-alkane method. Grazing at HSR was suspended 18 d before MSR and LSR (35 vs. 53 d), due to the low biomass availability. Over the first 35 d of grazing, the HSR reduced height and availability of herbage. The herbage intake and milk yield of goats increased from HSR to LSR, without relevant changes in milk quality. During all grazing period (53 d), the higher grazing pressure led to a lower total milk yield per goat, whereas the HSR produced the highest daily and total milk amount per ha.

Relationships between dietary factors and milk urea nitrogen level in goats grazing herbaceous pasture

Abstract This investigation aimed to individuate the dietary factors affecting the milk urea nitrogen (MUN) concentration in goats grazing herbaceous pasture and, particularly, to verify the relationship linking the diet crude protein (CP) content to MUN. A total of 205 individual observations regarding dietary and milk variables of 37 Girgentana goats involved in two experiments were used. Goats, averaging 154±14 days in milk and 38.1±5.4 kg of live weight, grazed on swards and received 500 g/d of barley meal. Sward biomass, herbage selected by goats and individual milk yield were measured and sampled weekly. The herbage intake and diet digestibility were estimated by the n-alkane method. Milk urea content was determined by an enzymatic method and transformed in MUN (MUN=urea*0.4665). The MUN concentration (9.7-35.4 mg/dl) was positively correlated with diet CP content (13.7-26.0% of dry matter (DM); r=0.76; P<0.001), pasture allowance (39-151 kg DM/goat; r=0.42; P<0.001), diet net energy for lactation concentration (NEl) (1.5-1.9 Mcal/kg DM; r=0.37; P<0.001) and milk yield (320-2250 g/d; r=0.25; P<0.001), and negatively related with NDF (18.7-37.4% DM; r=-0.69; P<0.001) and diet digestibility (72.6-92.5%; r=-0.33; P< 0.001). The stepwise selection from dietary variables and milk yield showed dietary CP percentage to be the single variable explaining the most variation in MUN (R2=0.56; P< 0.0001). The other variables entering into the model were diet NDF, 3.5% fat-corrected milk (FCM), DM intake and NDF intake (total R2=0.66). Including the CP/NEl and CP/NDF ratios of diet in the stepwise regression model, the CP/NDF ratio alone explained 60.1% of MUN variability, followed by barley proportion in the diet, FCM and diet CP concentration, absorbing an extra 4.6% of MUN variability. A linear regression, fitting mean feeding treatment per time data of MUN and dietary CP concentration (n=28)[CP(% of DM)=6.91±1.42+0.61±0.06*MUN (mg/dl); R²=0.79; P<0.0001], suggests that MUN could be used for predicting the CP content of the diet, as a tool for developing feeding strategies aimed at balancing the rations of grazing goats through adequate supplementation. Further data from experiments on grazing goats in different environmental conditions are required in order to define a more robust relationship by which to predict the dietary CP content by MUN.

Neuroendocrine responses in neonatal mother-deprived rabbits.

To study both short- and long-term adaptation mechanisms activated by rabbits which were separated from their mothers (DLS) for 48 h between postnatal days 9 and 11, we examined plasma corticosterone concentrations before, during, and after DLS as well as the expression of glucocorticoid receptor (GR) in the hippocampus and the adrenal axis responses to a mild stress stimuli or exogenous ACTH injection. At postnatal day 10, plasma corticosterone concentration of DLS rabbits was similar to that of controls, but rose two-fold at day 11 (17.7 + or - 1.3 vs. 9.3 + or - 1.2 microg/dl, P<0.01) and then decreased at day 12, when suckling was allowed again, to match those of controls with no difference thereafter. At postnatal day 14, both control and DLS rabbits had similar basal corticosterone concentrations (2.2 + or - 0.4 vs. 2.3 + or - 1.1 microg/dl, respectively) as well as at day 120 (8.8 + or - 3.2 vs. 9.7 + or - 2.8 microg/dl, respectively). After the standardized stress stimulus, plasma corticosterone concentrations were lower in DLS rabbits than controls at postnatal days 14 (P<0.01) and 120 (P<0.05). At day 120, corticosterone levels rose similarly seven-fold (P<0.01) within 30 min after ACTH administration and remained sustained thereafter in both control and DLS rabbits. Positive immunoreactivity for GR was detected in the hippocampus and in the dorsal medial hypothalamic region at postnatal day 14. The present data suggest that 48 h DLS from postnatal days 9 to 11 results in a modified hypothalamic-pituitary-adrenal axis reactivity later in life.

Milk production and physiological traits of ewes and goats housed indoor or grazing at different daily timing in summer

Abstract During a 6 week trial in summer, 3 homogeneous groups, each consisting of 5 Comisana ewes and 5 Rossa Mediterranea goats, grazed watered forage resources during day (D) or night (N), or were housed indoor and supplied with mowed (H). Maximum THI peaked at 94 at the end of July, and herbage was almost constantly higher of 80. Milk yield was higher in N than in D and H goats, whereas N ewes produced more milk than H group, but their milk yield was higher than D ewes only in the period with the highest THI values. The lower urea in N goat milk, and the higher casein in N ewe milk, seem to indicate a better efficiency in dietary nitrogen utilization of night grazing animals. N ewes showed lower SCC in milk, and higher incidence of clotting milk samples, in comparison to other ewes. N goats and ewes showed lower rectal temperature and pulse rate in the afternoon and, among metabolic parameters, higher hematic level of sodium. Night grazing was confirmed to be a management practice for increasing heat tolerance, to which goats appeared to be more sensitive in terms of milk yield.

Effects of feeding green forage of sulla (Hedysarum coronarium L.) on lamb growth and carcass and meat quality

The nutritional effects of sulla (Hedysarum coronarium L.) forage containing condensed tannins (CT) on growth of lambs, and carcass and meat quality were investigated. Thirty-two male Comisana lambs aged 100 ± 8 days weighing 19.0 ± 2.8 kg were fed fresh forage of sulla or CT-free annual ryegrass (Lolium multiflorum Lam. subsp. Wersterwoldicum) for 49 days until slaughter; in addition, each lamb was supplied with 200 g/days of concentrate. Eight lambs per diet had been previously treated with anthelmintic drugs to remove nematode parasites. Measurements of BW and feed intake, and counts of faecal nematode eggs were made. Carcass parameters were recorded after slaughter, and tissue components of the hind leg were determined. Longissimus dorsi meat was evaluated for pH, colour, thawing and cooking losses, Warner-Bratzler shear force, chemical composition and sensory properties based on triangle tests. Relative to ryegrass-fed lambs, sulla-fed lambs had significantly greater dry matter (DM) and protein intake, a more favourable feed conversion ratio, and superior growth rate, final BW at 150 days of age, carcass weight, yield and fatness. These results were attributed to the high protein and non-structural carbohydrate content of sulla, and also to the moderate CT content of sulla (16.7 and 20.3 g/kg of DM in offered and consumed sulla forage, respectively). Anthelmintic treatment did not affect lamb growth, as the level of parasitic infection (initial and final) was low. The physical, chemical and sensory properties of the lamb meat were not influenced by diet.