the inventors have unexpectedly discovered that the encapsulation of porcine seminal material as described in patent ep 0 922 451 induced & lt ;& lt ; toxicity & gt ;& gt ; ( or & lt ;& lt ; stress & gt ;& gt ;) for porcine spermatozoa present in the obtained capsules or for free ( non - encapsulated ) spermatozoa , but put into contact with these capsules . in particular , the inventors have unexpectedly discovered that at least two products present in these capsules are capable of generating this & lt ;& lt ; toxicity & gt ;& gt ; ( or & lt ;& lt ; stress & gt ;& gt ;) affecting the properties of porcine spermatozoa . the inventors have demonstrated for the first time that a barium solution , in particular the barium ions present in the solution , as well as sodium alginate or polymerized alginate present in these capsules alter the essential properties ( such as the motility ) of porcine spermatozoa . these detrimental effects on porcine spermatozoa are demonstrated in tables 1 and 2 which show the result of a & lt ;& lt ; toxicity & gt ;& gt ; ( or & lt ;& lt ; stress & gt ;& gt ;) test obtained by adding barium chloride ( bacl 2 at 5 or 10 %) on free semen and show after two days a significant reduction in the motility of the spermatozoa . in order to obtain efficient fertilization , more than 50 % of the spermatozoa have to be & lt ;& lt ; motile & gt ;& gt ; ( i . e . having an individual displacement velocity of more than 20 micrometers per second ). both values ( x - y ) mentioned in this table are the result of two measurements : the first value ( x ) over 100 means that x spermatozoa over 100 have a motility of more than 20 micrometers per second ( x so - called motile spermatozoa ) the second value ( y ) over 100 means that y of these same 100 spermatozoa have a same displacement velocity greater than or equal to 80 micrometers per second ( y so - called progressive spermatozoa ). table 3 shows the effect of the number of capsules ( beads ) having a size comprised between 50 μm and 8 mm , on the motility of spermatozoa after 1 and 3 days . gedil ® is a diluting agent consisting of a biological medium favorable to preservation of spermatozoa . the inventors also diluted the spermatozoa in media other than gedil ® and also observed a & lt ;& lt ; toxicity & gt ;& gt ; ( or & lt ;& lt ; stress & gt ;& gt ;) induced by addition of bacl 2 . motility of the spermatozoa is affected : the obtained movements are fluid with the addition of 4 beads ( capsules ) and the movements are jerky with the addition of 20 beads ( capsules ). the inventors also diluted the spermatozoa in media other than gedil ® and also observed toxicity proportional to the number of added beads ( capsules ). in order to reduce the harmful effect of these products ( toxic ), the inventors obtained a reduction in the global proportion of these toxic elements in the composition of the invention , by achieving concentration of the porcine seminal liquid and of the spermatozoa present in these capsules . this operation is obtained by removing a large proportion of seminal plasma present in this porcine seminal material to be encapsulated . consequently , the concentration of porcine spermatozoa in the capsules increases significantly , which leads to reducing the amount of these capsules and of these ( toxic ) elements from these capsules in the final composition obtained consisting of encapsulated spermatozoa and of free spermatozoa ( i . e . non - encapsulated spermatozoa ), and optionally of diluting agent . the present invention will be described in detail in the examples below shown as a non - limiting illustration of the invention . porcine semen is collected and arrives in the laboratory at a temperature of the order of 33 ° c . to 35 ° c . it is measured as for its concentration , its volume and its color , and then introduced into a centrifuge rotating at about 800 g , for a duration of about 10 minutes . by this centrifugation , about ⅔ of the supernatant ( containing seminal plasma ) are removed and measured as to their concentration by substraction in order to determine the amount of remaining spermatozoa , ⅓ of the preserved volume containing the essential of the spermatozoa , is intended to be encapsulated . the spermatozoa concentration within the seminal material intended to be encapsulated may also be accomplished by other techniques well known to one skilled in the art , such as sedimentation ( for example upon a temperature shift of about 17 ° c .) or by filtration on a membrane ( for example a membrane of about 0 . 1 μm ) so as to remove or reduce a significant proportion ( i . e . more than 50 %, preferably more than 65 %, still preferably more than 75 % or more than 85 %) of seminal plasma . this fraction is mixed beforehand with a barium solution ( addition of an aqueous ( solution ) saturated with barium chloride — 215 g of barium chloride in powder per liter — in order to obtain a final concentration of barium ions of 25 mmol / l ), and then injected dropwise into a solution of sodium alginate with stirring ( sodium alginate in solution ; 0 . 01 % to 1 % by weight per volume ). it is thus possible to inject about 500 ml of sperm added with barium chloride in a bath of 20 liters of sodium alginate . the capsules ( beads ) are instantaneously formed in contact with the periphery of the drop and thickened during several tens of minutes . the spermatic material encapsulated in the sodium alginate film ( gel ), and comprising more than 900 million spermatozoa per milliliter , is then separated by simple filtration . after washing , the capsules ( beads ) are recovered in a separation basket and then quantified in volume . next , they are mixed with a fraction of diluted free seminal material ( comprising about 33 million spermatozoa per milliliter ). this mixture of a free fraction combined with an encapsulated fraction allows fertilization of a sow , if the ovulation of the sow is located within the few following hours and thus allows fertilization to be obtained on a longer period , by postponed release of the encapsulated spermatozoa later on . the obtained composition is then injected into a probe , for which the inlet and outlet orifices have been adapted for letting through the capsules ( a diameter of about 0 . 8 cm ). this & lt ;& lt ; encapsulated fraction & gt ;& gt ; represents a volume of capsules containing about 1 . 5 to 2 . 5 thousand million spermatozoa . alternatively , the encapsulated fraction which represents a volume of capsules beads containing from about 1 . 5 to about 2 . 5 thousand million spermatozoa is mixed with the free fraction , diluted and containing between about 1 . 5 thousand million and about 2 . 5 thousand million spermatozoa present in a suitable diluting agent . both of these fractions are globally mixed with stirring . the ovulation was introduced by weaning without adding any hormones . detection of heat in sows is measured twice a day from the 3 rd day after weaning . insemination is carried out after detection of ovulation . a possible gestational state measured by echography and the whole of the data are measured . on the whole , the inventors notice an increase in the number of gestations in sows fertilized with the composition of the invention ( where the spermatozoa were concentrated before encapsulation ) as compared with sows fertilized by a composition without any concentration , and this for a same number of ( both free and encapsulated ) spermatozoa .
a porcine seminal material composition intended for artificial insemination of sows includes capsules containing a suspension made of porcine seminal material coated with a bi - valent or tri - valent ion alginate film , wherein the porcine spermatozoon concentration within the porcine seminal material suspension present in the capsules is between 900 and 1500 million spermatozoa per milliliter .