Evaluation of a diet free of animal protein in germfree swine.

BACKGROUND: Two experiments were conducted in which germfree pigs or pigs monoassociated with Lactobacillus paracasei subspecies paracasei were fed either a traditional milk-based diet (Esbilac) or an experimental diet free of animal protein (DFAP). METHODS: Throughout the 16-day study, animals' clinical condition, total weight gain, feed conversion, and bacterial contamination were monitored. At the conclusion of the study the animals were killed, necropsied and tissues sampled for L. paracasei isolation. RESULTS: General pig disposition remained consistent between treatment groups and trials, except for two animals that developed mild diarrhoea during trial 1. All pigs remained viable during the study irrespective the diet fed or probiotic inoculation. Germfree pigs fed the Esbilac diet gained on average a total of 1034 +/- 63.0 g, and had a feed conversion ratio of 0.17 +/- 0.01 g of gain per 1 ml of diet. Germfree pigs fed the experimental diet gained on average a total of 599 +/- 151 g, and had a feed conversion ratio of 0.10 +/- 0.02 g of gain per 1 ml of diet. Monoassociated pigs fed the Esbilac diet gained on average a total of 862 +/- 70.3 g, and had a feed conversion ratio 0.14 +/- 0.01 g of gain per 1 ml of diet. Monoassociated pigs fed the experimental diet gained on average a total of 563 +/- 96.8 g, and had a feed conversion ratio of 0.09 +/- 0.02 g of gain per 1 ml of diet. Lactobacillus paracasei established extensively in pigs fed either the Esbilac or experimental diets. Lactobacillus paracasei had no effect (P >0.05) on piglet growth and did not display any interactions based on the diet fed. Measured growth parameters were statistically different (P <0.05) based on the diet fed and variance seen between trials. CONCLUSION: In conclusion, a DFAP has been developed and has been shown to be capable of sustaining life in piglets up to 16 days of age.

Transitory changes of hormones in the plasma of parturient pony mares.

Frequent blood samples were collected from 8 pony mares before, during and after labour, parturition and placental expulsion and assayed for progesterone, oestradiol, androstenedione and LH concentrations by radioimmunoassay. A significant (P less than 0.05) decrease in progesterone, oestradiol and in the progesterone:oestradiol ratio was not detected until 0.5 h after foaling. Androstenedione concentrations rose before and peaked at parturition and then declined. A significant (P less than 0.05) rise in LH was detected 0.5 h after parturition. This LH peak was not detected in one mare and she was the only mare that did not ovulate within the first 20 days post partum. These results suggest that: (1) the foal may be an important factor in the production of progesterone and oestradiol by the feto-placental unit; (2) the pituitary is capable of releasing LH immediately after parturition; (3) the parturient rise in LH may be due to removal of negative feedback inhibition by progesterone and/or oestradiol; and (4) the parturient rise in LH at parturition, combined with already elevated concentrations of FSH, may be involved in the rapid growth of follicles post partum.

Absence of sexual dimorphism in the goat: Induction of luteinizing hormone discharge in the castrated male and female and in the intersex with estradiol benzoate.

Gonadectomized male (n = 5) and female (n = 5) and intact intersex goats (n = 2) were injected i.m. with 50 mug 17(beta)-estradiol benzoate (EB). After treatment, there was a transient 6- to 9-hr decrease in circulating levels of LH followed by a preovulatory-like discharge of LH in all goats. Release peaked at 12 to 18 hr after EB treatment. The magnitude of discharge and the time from treatment until peak of release were not influenced by the goat's sex. These findings suggested that the positive feedback effects of estrogen on LH release were not sexually differentiated in the goat. Since tonic concentrations of LH prior to EB treatment were not different among the groups, the studies also suggested that the intersex goats lacked the inhibitory gonadal influences on gonadotropin release that characterize intact animals.

Identification of a gonadotropin-releasing hormone-like factor in the rabbit fetal placenta.

The biological and immunological gonadotropin-releasing hormone (GnRH)-like activities in rabbit fetal placentas collected at Day 18 of gestation were investigated. Both crude and partially purified acid extracts of placental tissue were tested. A similarly prepared liver extract served as a control. Immunological GnRH-like activity, determined through a GnRH radioimmunoassay was 1.3-2.0 pg/mg protein for the crude placental extract, 7.1-9.2 pg/mg protein for the partially purified placental extract and was nondetectable for liver extract. Both the crude and partially purified placental extracts increased (P less than 0.01) luteinizing hormone (LH) release by dispersed rabbit pituitary cells, whereas the liver extract had no effect. The (Ac-D-p-Cl-Phe1,2, D-Trp3, D-Arg6, D-Ala10)-GnRH antagonist was used to determine whether the biological GnRH-like activity in the placental extract was mediated through GnRH receptors. All three doses of antagonist (10, 100 and 1000 ng) suppressed the biological GnRH-like activity in the placental extracts. Molecular sieve chromatography of the partially purified placental extract showed that the immunoreactive GnRH-like factor eluted in the same fractions as the GnRH standard. These data indicate that the rabbit fetal placenta has both immunological and biological GnRH-like activity.

Relationship between the level of estrone sulfate in the plasma and the number of fetuses during pregnancy in the gilt.

Estrone sulfate was measured in the plasma of pregnant and nonpregnant gilts between Days 10 and 32 after estrus. Estrone sulfate was found to rise sharply in pregnant gilts beginning at Day 18 and to decline at Day 30 to Day 32. Estrone levels were not related to litter size. The level of estrone sulfate on Days 20, 22, 24 and 26 was significantly correlated with litter size at slaughter on Day 32. Reduction of the number of live fetuses by crushing them in utero at Day 40 or between Days 30 to 60 did not cause a subsequent reduction in the level of estrone sulfate, whereas reduction at Day 24 did cause a decline in estrone sulfate. The level of estrone sulfate in plasma of gilts at 20 to 28 days after mating was higher in pregnant than in nonpregnant gilts. The relative level of estrone sulfate would enable one to estimate litter size at Days 20 to 28 days but not later. Because of the limitations of the assay in exact quantitation of the levels of estrone sulfate, the results can only be considered qualitative.

Induction of male sex behavior in ewes with silastic implants containing testosterone propionate.

In the first of two experiments, ovariectomized ewes with silastic implants containing testosterone propionate had higher concentrations of plasma testosterone than ovariectomized ewes with silastic implants containing testosterone (4.0+/-.2 vs .8+/-.1 ng/ml). In the second experiment, one or two 10 cm silastic implants filled with testosterone propionate increased concentrations of plasma testosterone and induced male sex behavior in ovariectomized ewes similar to plasma testosterone levels and male sex behavior in rams. The interval from initiation of the treatment to the first behavior test in which mounting was consistently observed was 14.4+/-2.9 days and once mounting behavior was consistently induced, the testosterone treated ewes mounted estrous ewes an average of 10.7+/-1.3 times during a 10-minute test.

Reproductive hormone secretions and first service conception rate subsequent to ovulation control with Synchro-Mate B.

Two groups of beef females receiving suboptimal energy diets were treated with Synchro-Mate B to control ovulation. The first group consisted of 30 suckled cows and 16 heifers. These females were bled 10 days and immediately prior to the implantation of norgestomet implants, at implant removal, 24, 27, 30, 33 and 36 hours and 9 and 16 days post-implant removal. The second group which consisted of 40 cows and 8 heifers was handled in the same manner except no blood samples were collected from 24 to 36 hours following implant removal. Calves were removed from all the cows for 48 hours, beginning at implant removal. All animals were artifically inseminated 48 hours following implant removal. Blood plasma was assayed for concentrations of progesterone and LH. The first service conception rate was 21% and 40% for groups 1 and 2. Several factors were identified that reduced the first service conception rate. In summary, Snychro-Mate B is an effective method to synchronize estrus in cattle. However, stress subsequent to implant removal should be avoided in order to obtain a higher first service conception rate.