The reproductive performance of female goats treated with melatonin is not improved after introduction to bucks displaying springtime sexual activity if these does are experiencing decreasing body weight/condition score

Abstract

Title: The reproductive performance of female goats treated with melatonin is not improved after introduction to bucks displaying springtime sexual activity if these does are experiencing decreasing body weight/condition score Authors: L.A. Zarazaga, M.C. Gatica, L. Gallego-Calvo, J.L. Guzmán PII:S0378-4320 (16) This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Highlights Reproductive activity of bucks is reduced in spring when male effect is used.  The response to the male effect decreases when females have an inadequate food supply.  Melatonin might reduce the negative effect of decreasing body weight-condition score.  Greater fecundity, fertility and productivity were observed in gain-melatonin does.  Plasma glucose and IGF-1 concentrations could explain the better reproductive results.3 AbstractThe aim of the present work was to determine whether treatment with melatonin modifies the reproductive response of female goats experiencing increasing or decreasing body weight (BW)/body condition score (BCS) when introduced to bucks displaying springtime sexual activity. During natural anoestrus, 53 does were isolated from bucks for a period of 42 days and distributed into two groups: 1) low BW/low BCS animals (N=24) (LLg group), which were fed 1.9 times their maintenance requirements so they would experience increasing BW and BCS; and 2) high BW/high BCS animals (N=29) (HHl group), which were fed 0.4 times their maintenance requirements so they would experience decreasing BW and BCS. Half of each group was treated, or not, with melatonin (LLg+Mel N=12, HHl+Mel N=15, LLg-Mel N=12 and HHlMel N=14). On 6th May they were introduced to six males, showing natural sexual activity, fitted with marking harnesses (thus permitting the detection of oestrous activity). The ovulation rate was assessed by transrectal ultrasonography and confirmed via the plasma progesterone concentration (measured twice per week in blood samples). Plasma glucose, IGF-1 and non-esterified fatty acid concentrations were also determined, along with the conception rate, fertility, prolificacy and productivity of the does. LH concentrations and LH pulsatility were also recorded in the hours around introduction to the males. 'Oestrous plus ovulation' was observed only in does treated with melatonin. A higher conception rate and greater fertility and productivity were observed among the LLg+Mel does. These females showed higher glucose and IGF-1 concentrations after the introduction of the males. LH concentrations increased after male introduction independent of all other conditions. In conclusion, the present results show that treatment w...

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“…Biogenic amines in crustaceans are classical neuroregulators which mediate and control the hemolymph glucose level through different mechanisms (Kuo et al, 1995 ; Girish et al, 2015 ; Zarazaga et al, 2017 ). However, studies referring to 5-HT and DA have yielded conflicting results about the eyestalk modulating hemolymph glucose or not in different species.…”

Photoperiod-Treatment in Mediterranean Bucks Can Improve the Reproductive Performance of the Male Effect Depending on the Extent of Their Seasonality

“…However, the degree of sexual behaviour displayed by the bucks determines the proportion of does that eventually ovulate [14][15][16]. To overcome this problem, exogenous melatonin [13][14][15][16] or photoperiod treatment could be used to induce the sexual activity of the bucks during spring by extra illumination for 2.5-3 months during the winter and followed by the natural photoperiod [17][18][19][20][21][22][23].…”

Melatonin supplement induced the hair follicle development in offspring rex rabbits

“…rodents), MT secretion is high in winter and reproductive activity is inhibited (Reiter et al., 1976). Therefore, studies of reproductive performance by implanting MT are usually performed on short‐day breeding animals such as goat (Ge et al., 2018; Nixon, Choy, Parry, & Pearson, 2010; Zarazaga, Gatica, Gallego‐Calvo, & Guzmán, 2017). MT is not normally used in the production of breeding rabbits, maybe because they have no obvious oestrus season (McNitt et al., 2013).…”