202 Source matters: long-term effects of nursery sanitary condition and dietary Zinc source and level on growth performance, diarrhea incidence, and carcass metrics of pigs

Abstract

Abstract There is growing evidence that requirements for particular nutrients increase when pigs are kept under low sanitary conditions (LSC). It may be hypothesized that dietary zinc (Zn) source can exert influence on immune status, which may influence resistance to subclinical and clinical diseases. The objective was to investigate the long-term effects of nursery sanitary condition and dietary Zn source and growth performance, diarrhea incidence, and carcass metrics of pigs. An experiment was performed with 480 mixed-sex weanling pigs (initial body weight = 6.4 ± 0.38 kg) which were assigned to 1 of 5 treatments during the nursery (42 d) as follows: 1) pigs housed in high sanitary conditions (HSC) and fed 50 mg/kg Zn from Zn-amino acid complex (ZnAA), pigs housed in LSC and fed either 2) 50 mg/kg Zn from ZnAA, 3) 100 mg/kg Zn from ZnAA, 4) 100 mg/kg Zn and 0.4 mg/kg chromium (Cr) from Zn+Cr-amino acid complex (Zn+CrAA), or 5) 100 mg/kg Zn from inorganic Zn (ZnSO4). Pigs were then placed onto a common grower (42 d) and finisher (42 d) diets and housed under similar, standard conditions and were monitored until slaughter. Growth performance, diarrhea incidence, and carcass characteristics were assessed. Pigs housed in LSC and fed 100 mg/kg from ZnSO4 had less average daily feed intake (ADFI) during wk 1 and 2 of nursery (0.29 vs. 0.33 ± 0.01 kg/d; P < 0.05) and poorer feed to gain (FGR) during wk 3 and 4 of nursery (1.76 vs. 1.54 ± 0.03 kg/kg; P < 0.05), compared with the other groups. Overall nursery FGR was poorer in pigs housed in LSC and fed 100 mg/kg from ZnSO4 compared with the other groups housed in LSC (1.63 vs. 1.54 ± 0.02 kg/kg; P < 0.05). Diarrhea incidence tended to increase in all groups housed in LSC compared with the group housed in HSC during week 1 of nursery (91.1 vs. 80.4 ± 3.11%; P < 0.10), while no effect on diarrhea incidence was observed during the subsequent week (P > 0.10). Slaughter weight was increased in pigs housed in LSC and fed 100 mg/kg Zn and 0.4 mg/kg Cr from Zn+CrAA compared with pigs housed in LSC and fed 100 mg/kg from ZnSO4 (123.4 vs. 120.1 ± 0.63 kg; P < 0.05). Housing pigs in LSC during the nursery seems to trigger negative effects on growth performance and diarrhea incidence during nursery only, but these effects do not seem to be translated into the grower and finisher phases. Feeding ZnAA and Zn+CrAA aid the pigs in responding to LSC during nursery and may be an approach to help minimize negative effects of immune system stimulation.