Colostrum and milk composition in terms of total fat, total proteins, caseins, lactose, urea, dry matter and SCC were analysed in triplicate, assayed using the infrared spectroscope Milkoscan FT2 (FOSS A/S, Padua, Italy).
The concentrations of IgA, IgG and IgM were quantified using an immunoglobulin ELISA procedure following the protocol described by Luise et al. [26 (link)]. For the analysis, the colostrum samples were diluted at 40,000, 500,000 and 10,000 for IgA, IgG and IgM, respectively, and the milk samples were diluted at 20,000, 2400 and 4000 for IgA, IgG and IgM, respectively. The reaction was quantified spectrophotometrically at an absorbance of 405 nm using a microplate reader (Multiskan FC Microplate Photometer – Thermo Fisher Scientific). The data regarding the Igs concentrations were calculated using a four-point parametric curve and were expressed as milligram per millilitre (mg/mL).
The concentration of insulin growth factors (IGF-1) was assayed using swine IGF-1 ELISA Quantitation Kits (SEA050Po Cloud Clone, Wuhan, China) according to the manufacturer’s instructions. The reaction was quantified spectrophotometrically at an absorbance of 450 nm using a microplate reader (Multiskan FC Microplate Photometer – Thermo Fisher Scientific). The concentrations of IGF-1 were calculated using a four-point parametric curve and were expressed as µg/mL.
The concentrations of putrescine, spermidine and spermine (nmol/mL) in the colostrum and milk were assessed using high-performance liquid chromatography and were quantified using fluorimetry, according to the method described by Pinna et al. [27 ].
The concentrations of IgA, IgG and IgM were quantified using an immunoglobulin ELISA procedure following the protocol described by Luise et al. [26 (link)]. For the analysis, the colostrum samples were diluted at 40,000, 500,000 and 10,000 for IgA, IgG and IgM, respectively, and the milk samples were diluted at 20,000, 2400 and 4000 for IgA, IgG and IgM, respectively. The reaction was quantified spectrophotometrically at an absorbance of 405 nm using a microplate reader (Multiskan FC Microplate Photometer – Thermo Fisher Scientific). The data regarding the Igs concentrations were calculated using a four-point parametric curve and were expressed as milligram per millilitre (mg/mL).
The concentration of insulin growth factors (IGF-1) was assayed using swine IGF-1 ELISA Quantitation Kits (SEA050Po Cloud Clone, Wuhan, China) according to the manufacturer’s instructions. The reaction was quantified spectrophotometrically at an absorbance of 450 nm using a microplate reader (Multiskan FC Microplate Photometer – Thermo Fisher Scientific). The concentrations of IGF-1 were calculated using a four-point parametric curve and were expressed as µg/mL.
The concentrations of putrescine, spermidine and spermine (nmol/mL) in the colostrum and milk were assessed using high-performance liquid chromatography and were quantified using fluorimetry, according to the method described by Pinna et al. [27 ].
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